Sounds like the new Flex TIme is messing you up. Turn it off for now -either the star, or in the editor for each track, turn off quantizing.
WORST CASE - If you didn't save the previous version of GarageBand (a good way to do this is control-click on the app, and "Compress" it - this saves an archive for you; do this before you install or upgrade), you could install the APP ONLY of GarageBand '09, and then open the same project, and turn off all "Enhance Timing" on the audio tracks (found in the editor - double click on the region to open it).
Then save, THEN open up into GB '11. Not sure if that will bypass the problem, but I think it would.
And, yes, it looks like they've made the Flex Time tool the easiest tool to get to - so be careful and watch the cursor in order to see what too is active while you're in the editor. You have to be in the lower part of the waveform in order to get the old standard cursor.
And the crashes - there have been a lot of posts on this, and I think someone said Apple knows about the issue already, so hopefully there will be a fix for it.