luacs1998

EAQ

Use the "Forge" profile.

If you run minecraft and all is fine then there's nothing wrong.

Have you tried Internet Explorer? (ya, it sucks, but beggars can't be choosers)

Run modded mc at least once through the vanilla launcher.

[lmgtfy]adding more memory to java[/lmgtfy]

If your host requires the server jar to be named in a certain way, don't rename the server jar. Rename the forge jar.

A mod is causing this problem. Identify which one, and remove it.

Read the EAQ/

We need LOGS. Give us LOGS. Get it from the DEVELOPMENT CONSOLE tab of your LAUNCHER. That specific enough for you?

Try running installer from cmd: java -jar minecraftforge-installer.jar cpw.mods.fml.installer.SimpleInstaller

Try using the normal mojang launcher.

Remove cofhcore from your mods folder.

It adds a profile; the profile is what keeps your forge updated.

FTB, Lex, as in Feed the Beast, not FTP. As an aside I am keeping copies of the fmllibs.zip s for those who aren't using the new launcher + installer or modpacks. PM me if you need them. (there shouldn't be a reason, unless you're using redpower/some other shit mod that hasn't updated)

The EAQ isn't updated, Lex ninja-deleted the old 1.4/1.5 library folder on files while I was at school -.- I'll rip a backup out of ftb. But seriously, what mod is keeping you from updating? RedPower? EDIT: EAQ links still work, I'll grab a backup just in case they go down.

Open cmd Run java -jar minecraftforge-installer.jar cpw.mods.fml.installer.SimpleInstaller

http://www.minecraftforge.net/forum/index.php/topic,12728.msg65980.html#msg65980

OS version? Console log?

Add this to jvm args: -XX:PermSize=256M

Run the installer from the command prompt, or see if you can upgrade to java 7.

Log?

Run modded minecraft through the mojang launcher at least once.

Console logs/jvm version/etc.

Read the EAQ.