Laggson

I downloaded the installer of the latest recommented for 1.6.4 (9.11.1.916), chose the forge-jar in the MagicLauncher (think it's much better than the official one) and tried to start. Get this error every time: (Btw, at 1.6.2 it worked perfectly..) Also I can't find a "ForgeModLoader-client-0.log" in my folder, probably wasn't even created.