I am using Windows 7, newest patch.

I used Installer to install Forge. That was installer forge-1.8-11.14.3.1450-installer-win.exe. Afterwards, I used jar version of that installer, still did the same.

It made folder for that release in %appdata%/.minecraft/versions, but it put only .json file there, not .jar. Only thing I can give is what was on my launcher development console:

Getting syncinfo for selected version
Queueing library & version downloads
Download job 'Version & Libraries' started (16 threads, 6 files)
Attempting to download C:\Users\User\AppData\Roaming\.minecraft\libraries\net\sf\jopt-simple\jopt-simple\4.5\jopt-simple-4.5.jar for job 'Version & Libraries'... (try 0)
Attempting to download C:\Users\User\AppData\Roaming\.minecraft\libraries\org\ow2\asm\asm-all\5.0.3\asm-all-5.0.3.jar for job 'Version & Libraries'... (try 0)
Attempting to download C:\Users\User\AppData\Roaming\.minecraft\libraries\lzma\lzma\0.0.1\lzma-0.0.1.jar for job 'Version & Libraries'... (try 0)
Attempting to download C:\Users\User\AppData\Roaming\.minecraft\libraries\io\netty\netty-all\4.0.15.Final\netty-all-4.0.15.Final.jar for job 'Version & Libraries'... (try 0)
Attempting to download C:\Users\User\AppData\Roaming\.minecraft\libraries\net\minecraft\launchwrapper\1.11\launchwrapper-1.11.jar for job 'Version & Libraries'... (try 0)
Attempting to download C:\Users\User\AppData\Roaming\.minecraft\versions\1.8-Forge11.14.3.1450\1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'... (try 0)
Couldn't download https://s3.amazonaws.com/Minecraft.Download/versions/1.8-Forge11.14.3.1450/1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'
java.lang.RuntimeException: Server responded with 403
at net.minecraft.launcher.updater.download.EtagDownloadable.download(EtagDownloadable.java:48)
at net.minecraft.launcher.updater.download.DownloadJob.popAndDownload(DownloadJob.java:112)
at net.minecraft.launcher.updater.download.DownloadJob.access$000(DownloadJob.java:15)
at net.minecraft.launcher.updater.download.DownloadJob$1.run(DownloadJob.java:94)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Delta time to compare resources: 1025 ms 
Download job 'Resources' skipped as there are no files to download
Job 'Resources' finished successfully
Attempting to download C:\Users\User\AppData\Roaming\.minecraft\versions\1.8-Forge11.14.3.1450\1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'... (try 1)
Finished downloading C:\Users\User\AppData\Roaming\.minecraft\libraries\lzma\lzma\0.0.1\lzma-0.0.1.jar for job 'Version & Libraries': Local file matches local checksum, using that
Finished downloading C:\Users\User\AppData\Roaming\.minecraft\libraries\org\ow2\asm\asm-all\5.0.3\asm-all-5.0.3.jar for job 'Version & Libraries': Local file matches local checksum, using that
Finished downloading C:\Users\User\AppData\Roaming\.minecraft\libraries\io\netty\netty-all\4.0.15.Final\netty-all-4.0.15.Final.jar for job 'Version & Libraries': Local file matches local checksum, using that
Finished downloading C:\Users\User\AppData\Roaming\.minecraft\libraries\net\minecraft\launchwrapper\1.11\launchwrapper-1.11.jar for job 'Version & Libraries': Local file matches local checksum, using that
Finished downloading C:\Users\User\AppData\Roaming\.minecraft\libraries\net\sf\jopt-simple\jopt-simple\4.5\jopt-simple-4.5.jar for job 'Version & Libraries': Local file matches local checksum, using that
Couldn't download https://s3.amazonaws.com/Minecraft.Download/versions/1.8-Forge11.14.3.1450/1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'
java.lang.RuntimeException: Server responded with 403
at net.minecraft.launcher.updater.download.EtagDownloadable.download(EtagDownloadable.java:48)
at net.minecraft.launcher.updater.download.DownloadJob.popAndDownload(DownloadJob.java:112)
at net.minecraft.launcher.updater.download.DownloadJob.access$000(DownloadJob.java:15)
at net.minecraft.launcher.updater.download.DownloadJob$1.run(DownloadJob.java:94)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Attempting to download C:\Users\User\AppData\Roaming\.minecraft\versions\1.8-Forge11.14.3.1450\1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'... (try 2)
Couldn't download https://s3.amazonaws.com/Minecraft.Download/versions/1.8-Forge11.14.3.1450/1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'
java.lang.RuntimeException: Server responded with 403
at net.minecraft.launcher.updater.download.EtagDownloadable.download(EtagDownloadable.java:48)
at net.minecraft.launcher.updater.download.DownloadJob.popAndDownload(DownloadJob.java:112)
at net.minecraft.launcher.updater.download.DownloadJob.access$000(DownloadJob.java:15)
at net.minecraft.launcher.updater.download.DownloadJob$1.run(DownloadJob.java:94)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Attempting to download C:\Users\User\AppData\Roaming\.minecraft\versions\1.8-Forge11.14.3.1450\1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'... (try 3)
Couldn't download https://s3.amazonaws.com/Minecraft.Download/versions/1.8-Forge11.14.3.1450/1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'
java.lang.RuntimeException: Server responded with 403
at net.minecraft.launcher.updater.download.EtagDownloadable.download(EtagDownloadable.java:48)
at net.minecraft.launcher.updater.download.DownloadJob.popAndDownload(DownloadJob.java:112)
at net.minecraft.launcher.updater.download.DownloadJob.access$000(DownloadJob.java:15)
at net.minecraft.launcher.updater.download.DownloadJob$1.run(DownloadJob.java:94)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Attempting to download C:\Users\User\AppData\Roaming\.minecraft\versions\1.8-Forge11.14.3.1450\1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'... (try 4)
Couldn't download https://s3.amazonaws.com/Minecraft.Download/versions/1.8-Forge11.14.3.1450/1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'
java.lang.RuntimeException: Server responded with 403
at net.minecraft.launcher.updater.download.EtagDownloadable.download(EtagDownloadable.java:48)
at net.minecraft.launcher.updater.download.DownloadJob.popAndDownload(DownloadJob.java:112)
at net.minecraft.launcher.updater.download.DownloadJob.access$000(DownloadJob.java:15)
at net.minecraft.launcher.updater.download.DownloadJob$1.run(DownloadJob.java:94)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Attempting to download C:\Users\User\AppData\Roaming\.minecraft\versions\1.8-Forge11.14.3.1450\1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'... (try 5)
Couldn't download https://s3.amazonaws.com/Minecraft.Download/versions/1.8-Forge11.14.3.1450/1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'
java.lang.RuntimeException: Server responded with 403
at net.minecraft.launcher.updater.download.EtagDownloadable.download(EtagDownloadable.java:48)
at net.minecraft.launcher.updater.download.DownloadJob.popAndDownload(DownloadJob.java:112)
at net.minecraft.launcher.updater.download.DownloadJob.access$000(DownloadJob.java:15)
at net.minecraft.launcher.updater.download.DownloadJob$1.run(DownloadJob.java:94)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Gave up trying to download https://s3.amazonaws.com/Minecraft.Download/versions/1.8-Forge11.14.3.1450/1.8-Forge11.14.3.1450.jar for job 'Version & Libraries'
Job 'Version & Libraries' finished with 1 failure(s)!

Also, I got txt file where the jar installer was. It contained:

Considering library net.minecraftforge:forge:1.8-11.14.3.1450: Not Downloading
Considering library io.netty:netty-all:4.0.15.Final: Not Downloading
Considering library net.minecraft:launchwrapper:1.11: Not Downloading
Considering library org.ow2.asm:asm-all:5.0.3: Not Downloading
Considering library com.typesafe.akka:akka-actor_2.11:2.3.3
Checking "C:\Users\User\AppData\Roaming\.minecraft\libraries\com\typesafe\akka\akka-actor_2.11\2.3.3\akka-actor_2.11-2.3.3.jar" internal checksums
    checksums.sha1 validated successfully
    Jar contents validated successfully
Considering library com.typesafe:config:1.2.1
Checking "C:\Users\User\AppData\Roaming\.minecraft\libraries\com\typesafe\config\1.2.1\config-1.2.1.jar" internal checksums
    checksums.sha1 validated successfully
    Jar contents validated successfully
Considering library org.scala-lang:scala-actors-migration_2.11:1.1.0
Checking "C:\Users\User\AppData\Roaming\.minecraft\libraries\org\scala-lang\scala-actors-migration_2.11\1.1.0\scala-actors-migration_2.11-1.1.0.jar" internal checksums
    checksums.sha1 validated successfully
    Jar contents validated successfully
Considering library org.scala-lang:scala-compiler:2.11.1
Checking "C:\Users\User\AppData\Roaming\.minecraft\libraries\org\scala-lang\scala-compiler\2.11.1\scala-compiler-2.11.1.jar" internal checksums
    checksums.sha1 validated successfully
    Jar contents validated successfully
Considering library org.scala-lang.plugins:scala-continuations-library_2.11:1.0.2
Checking "C:\Users\User\AppData\Roaming\.minecraft\libraries\org\scala-lang\plugins\scala-continuations-library_2.11\1.0.2\scala-continuations-library_2.11-1.0.2.jar" internal checksums
    checksums.sha1 validated successfully
    Jar contents validated successfully
Considering library org.scala-lang.plugins:scala-continuations-plugin_2.11.1:1.0.2
Checking "C:\Users\User\AppData\Roaming\.minecraft\libraries\org\scala-lang\plugins\scala-continuations-plugin_2.11.1\1.0.2\scala-continuations-plugin_2.11.1-1.0.2.jar" internal checksums
    checksums.sha1 validated successfully
    Jar contents validated successfully
Considering library org.scala-lang:scala-library:2.11.1
Checking "C:\Users\User\AppData\Roaming\.minecraft\libraries\org\scala-lang\scala-library\2.11.1\scala-library-2.11.1.jar" internal checksums
    checksums.sha1 validated successfully
    Jar contents validated successfully
Considering library org.scala-lang:scala-parser-combinators_2.11:1.0.1
Checking "C:\Users\User\AppData\Roaming\.minecraft\libraries\org\scala-lang\scala-parser-combinators_2.11\1.0.1\scala-parser-combinators_2.11-1.0.1.jar" internal checksums
    checksums.sha1 validated successfully
    Jar contents validated successfully
Considering library org.scala-lang:scala-reflect:2.11.1
Checking "C:\Users\User\AppData\Roaming\.minecraft\libraries\org\scala-lang\scala-reflect\2.11.1\scala-reflect-2.11.1.jar" internal checksums
    checksums.sha1 validated successfully
    Jar contents validated successfully
Considering library org.scala-lang:scala-swing_2.11:1.0.1
Checking "C:\Users\User\AppData\Roaming\.minecraft\libraries\org\scala-lang\scala-swing_2.11\1.0.1\scala-swing_2.11-1.0.1.jar" internal checksums
    checksums.sha1 validated successfully
    Jar contents validated successfully
Considering library org.scala-lang:scala-xml_2.11:1.0.2
Checking "C:\Users\User\AppData\Roaming\.minecraft\libraries\org\scala-lang\scala-xml_2.11\1.0.2\scala-xml_2.11-1.0.2.jar" internal checksums
    checksums.sha1 validated successfully
    Jar contents validated successfully
Considering library lzma:lzma:0.0.1: Not Downloading
Considering library net.sf.jopt-simple:jopt-simple:4.5: Not Downloading

What should I do?

If there are needed any other logs, please tell me where to find them.

I am using SkaiaCraft, but still problem is with installer, as installer placed ONLY json file in version folder, not jar file.

The problem is not with the installer, it is with you using a cracked launcher instead of buying the game. Go buy the game and use the official minecraft launcher.

buy the game