LexManos

Whatever service or mod you're using is adding a custom logging system which is breaking the one MC/Forge uses. I'd talk to your server host if they are the ones applying that logging.

NBT data is not synced between the client and server. So if you change anything on the server you will need to send a packet to inform the client that it's changed.

No, you're not. Unless you just lied and said you removed everything as this is a error caused by a mod you installed. And if you truly did remove everything that mod would not be there. As always always always post logs.

Run the jar from the console and give us the logs. Or manually install the libraries like it says in the eaq.

Give me directory listings.

Assume you're talking about a linuz system and ~ being your home dir, no, it needs to be in the minecraft/libs dir.

Always post with logs.

Interesting, i'm not able to reproduce in just forge. Does this happen on all servers, or just the MCPC server you showed. Also, try removing microblocks and trying. Note: MicroBlocks/Multipart is not part of Forge and if theya re the issue we cant support it.

Ya gunna lock this, I can just see this becoming a major issue/flamewar... no offense intended, just don't wanna deal with that crap.

Interesting, something is corrupting your class file. I would say it's a coremod that is broken. You can try running with -Dlegacy.debugClassLoading=true and pastebin-ing the log.

Well show us what DOES happen when you try and run it manually. And if you don't know how to get a md5 of a file, there's this wonderful invention called google -.- Fixing issues requires a little cooperation on your end.

Odd, try running the jar manually. Also, what is the md5 of the installer jar you have?

Rensik has been banned for being a cunt. The answer provided in the first place was perfectly fine. Don't get all huffy.

You have A LOT of mods in there that are erroring/derping up. Your best bet is to track down which of the coremods are in there are editing things that it shouldn't. I see a lot of errors trying to download the players skin, may be the cause.

Use the recomended build, or manually build the classpath, there was a slight bug with the gradle switch, post-gradle 1.6.4 builds are not advised to be used.

NEI needs CodeChickenCore not CodeChickenLib

Give us a console log of you running the installer.

By removing the mods, and trying again.

The ones specified in the json.

You have a mod installed thats trying to load client side code, and isnt compatible with the dedicated server you'll need to track that down/.

Use the recomended build.

Use the installer.

Gradle makes this obsolete, Also looking at it, this doesnt actually do jack shit besides display a random gui. And pro-tip GUI's wont work on headless servers such as build servers! Ya... No...

Its not a gui feature as it's part of the boot strap. Pass it to THE LAUNCHER. The jar or exe file you download from minecraft.net Ya, that.

https://github.com/MinecraftForge/MinecraftForge/commit/295542c3579d75368b9ce59333b8f6aeff20d5e4#commitcomment-4678117