Freezes and Crashes/iMovie 2

[Trbl007 at aol.com]

I imported a 20 minute video via firewire from my Canon ZR 10 camcorder to my 
 external 30 G VST Firewire hard drive that was mounted via firewire on my 
9.54 G G4 computer.  I am using system 9.1 with 64 mb built in memory.

Everything would work well for a bit (I would do some editing) and then the 
computer would either freeze up or bomb.  I would also get a finder message 
like the finder has quit or the finder needs attention or a message such as 
iMovie has quit.

Any help you all could give me would be very much appreciated.

Thank you!

Marilyn