You have 32-bit Windows 7, and thus 32-bit Java. This limits the amount of RAM you can assign through the FTB luancher, and thus, cannot assign enough RAM to run almost all of the 1.6.4 FTB packs. The only 1.6.4 FTB pack that's designed to run on 32-bit systems is FTB Lite 2. Please try running that, and if it too crashes, please post a new console log to pastebin.com and link it here.
Your only real "solution" is to upgrade to a 64-bit OS, which will allow you to use 64-bit Java.