So I downloaded a mod and I put in my mods folder and then I start up Minecraft and this pops up. I don't know what to do. If anyone could help that would be great!

Picture: https://imgur.com/AXHpLsM

14 minutes ago, diesieben07 said:

Update Forge.

Do I just download the latest file and install client? That's what I did and every time I create a world it crashes with: 

The game crashed whilst exception in server tick loop
Error: java.lang.NoClassDefFoundError: net/minecraft/world/ServerWorld

Spoiler

---- Minecraft Crash Report ----
// Sorry

Time: 7/30/19 12:40 PM
Description: Exception in server tick loop

java.lang.NoClassDefFoundError: net/minecraft/world/ServerWorld
    at com.sk89q.worldedit.forge.ForgeWorldEdit.setupPlatform(ForgeWorldEdit.java:133) ~[?:?] {}
    at com.sk89q.worldedit.forge.ForgeWorldEdit.serverStarted(ForgeWorldEdit.java:192) ~[?:?] {}
    at net.minecraftforge.eventbus.ASMEventHandler_1_ForgeWorldEdit_serverStarted_FMLServerStartedEvent.invoke(.dynamic) ~[?:?] {}
    at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80) ~[eventbus-0.10.6-service.jar:?] {}
    at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258) ~[eventbus-0.10.6-service.jar:?] {}
    at net.minecraftforge.fml.server.ServerLifecycleHooks.handleServerStarted(ServerLifecycleHooks.java:81) ~[?:?] {}
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:598) [?:?] {pl:accesstransformer:B}
    at java.lang.Thread.run(Thread.java:745) [?:1.8.0_51] {}
Caused by: java.lang.ClassNotFoundException: net.minecraft.world.ServerWorld
    at java.lang.ClassLoader.findClass(ClassLoader.java:530) ~[?:1.8.0_51] {}
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_51] {}
    at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:102) ~[modlauncher-3.1.0.jar:?] {}
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_51] {}
    ... 8 more

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- System Details --
Details:
    Minecraft Version: 1.14.4
    Minecraft Version ID: 1.14.4
    Operating System: Windows 10 (amd64) version 10.0
    Java Version: 1.8.0_51, Oracle Corporation
    Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
    Memory: 1562629936 bytes (1490 MB) / 2147483648 bytes (2048 MB) up to 2147483648 bytes (2048 MB)
    CPUs: 4
    JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
    ModLauncher: 3.1.0+58+1395384
    ModLauncher launch target: fmlclient
    ModLauncher naming: srg
    ModLauncher services: 
        /eventbus-0.10.6-service.jar eventbus PLUGINSERVICE 
        /forge-1.14.4-28.0.24.jar object_holder_definalize PLUGINSERVICE 
        /forge-1.14.4-28.0.24.jar runtime_enum_extender PLUGINSERVICE 
        /accesstransformers-0.16.0-shadowed.jar accesstransformer PLUGINSERVICE 
        /forge-1.14.4-28.0.24.jar capability_inject_definalize PLUGINSERVICE 
        /forge-1.14.4-28.0.24.jar runtimedistcleaner PLUGINSERVICE 
        /forge-1.14.4-28.0.24.jar fml TRANSFORMATIONSERVICE 
    FML: 28.0
    Forge: net.minecraftforge:28.0.24
    FML Language Providers: 
        [email protected]
    Mod List: 
        roadstuff-1.14.4-2.0.3.0.jar Road Stuff 2 {[email protected] DONE}
        worldedit-forge-mc1.14.2-7.0.1-beta-01 (1).jar WorldEdit {[email protected];c97071c DONE}
        forge-1.14.4-28.0.24-universal.jar Forge {[email protected] DONE}
    Player Count: 0 / 8; []
    Data Packs: vanilla, mod:worldedit, mod:roadstuff, mod:forge
    Type: Integrated Server (map_client.txt)
    Is Modded: Definitely; Client brand changed to 'forge'

I hope this is what you were talking about

7 minutes ago, diesieben07 said:

Post updated logs.

I hope this is what you were talking about

Spoiler

---- Minecraft Crash Report ----
// Sorry

Time: 7/30/19 12:40 PM
Description: Exception in server tick loop

java.lang.NoClassDefFoundError: net/minecraft/world/ServerWorld
    at com.sk89q.worldedit.forge.ForgeWorldEdit.setupPlatform(ForgeWorldEdit.java:133) ~[?:?] {}
    at com.sk89q.worldedit.forge.ForgeWorldEdit.serverStarted(ForgeWorldEdit.java:192) ~[?:?] {}
    at net.minecraftforge.eventbus.ASMEventHandler_1_ForgeWorldEdit_serverStarted_FMLServerStartedEvent.invoke(.dynamic) ~[?:?] {}
    at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80) ~[eventbus-0.10.6-service.jar:?] {}
    at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258) ~[eventbus-0.10.6-service.jar:?] {}
    at net.minecraftforge.fml.server.ServerLifecycleHooks.handleServerStarted(ServerLifecycleHooks.java:81) ~[?:?] {}
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:598) [?:?] {pl:accesstransformer:B}
    at java.lang.Thread.run(Thread.java:745) [?:1.8.0_51] {}
Caused by: java.lang.ClassNotFoundException: net.minecraft.world.ServerWorld
    at java.lang.ClassLoader.findClass(ClassLoader.java:530) ~[?:1.8.0_51] {}
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_51] {}
    at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:102) ~[modlauncher-3.1.0.jar:?] {}
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_51] {}
    ... 8 more

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- System Details --
Details:
    Minecraft Version: 1.14.4
    Minecraft Version ID: 1.14.4
    Operating System: Windows 10 (amd64) version 10.0
    Java Version: 1.8.0_51, Oracle Corporation
    Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
    Memory: 1562629936 bytes (1490 MB) / 2147483648 bytes (2048 MB) up to 2147483648 bytes (2048 MB)
    CPUs: 4
    JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
    ModLauncher: 3.1.0+58+1395384
    ModLauncher launch target: fmlclient
    ModLauncher naming: srg
    ModLauncher services: 
        /eventbus-0.10.6-service.jar eventbus PLUGINSERVICE 
        /forge-1.14.4-28.0.24.jar object_holder_definalize PLUGINSERVICE 
        /forge-1.14.4-28.0.24.jar runtime_enum_extender PLUGINSERVICE 
        /accesstransformers-0.16.0-shadowed.jar accesstransformer PLUGINSERVICE 
        /forge-1.14.4-28.0.24.jar capability_inject_definalize PLUGINSERVICE 
        /forge-1.14.4-28.0.24.jar runtimedistcleaner PLUGINSERVICE 
        /forge-1.14.4-28.0.24.jar fml TRANSFORMATIONSERVICE 
    FML: 28.0
    Forge: net.minecraftforge:28.0.24
    FML Language Providers: 
        [email protected]
    Mod List: 
        roadstuff-1.14.4-2.0.3.0.jar Road Stuff 2 {[email protected] DONE}
        worldedit-forge-mc1.14.2-7.0.1-beta-01 (1).jar WorldEdit {[email protected];c97071c DONE}
        forge-1.14.4-28.0.24-universal.jar Forge {[email protected] DONE}
    Player Count: 0 / 8; []
    Data Packs: vanilla, mod:worldedit, mod:roadstuff, mod:forge
    Type: Integrated Server (map_client.txt)
    Is Modded: Definitely; Client brand changed to 'forge'

 

6 minutes ago, diesieben07 said:

You installed a 1.14.2 mod on 1.14.4.

that must be the world edit. is there any world edit files that i can install on this version?

i have the same problem with 1.16.1 ...

(problem mod: "jei")