It's pretty "hard" to overload FL, that only happens when you hit 2gigs of RAM (the max size...or so I think)
Try watching the VST's that FLStudio is loading, and try to pinpoint the exact one it gets to when it crashes. As in, watch the top left of the screen (for FL8 and under) or the nice new project loader animated thingy in FL9.
Say the last thing you saw was "now loading reFx Vanguard":
- Go into your VST folder, remove the 'vanguard.dll' file, and put it somewhere else (just for the moment) and then try opening the program again. It SHOULD open, and bring up the message "the VST plugin "reFx vanguard" could not be found...blah blah blah"
Then try putting the .dll file back, refreshing the plugin list, and then replacing the Vanguard channels in the .flp.
Sounds kinda weird, but it's worked for me. Autotune was crashing FL for me at one point, and this fixed it for me.