I have a spinning ball problem in FCP with the following project:
I have imported clips from After Effects in Animation codec (I used it to chroma key). I captured the clips originally through FCP in Pro Res HQ format, then imported to AE and exported as Animation. Now, when I just click on the timeline in FCP , the spinning ball of death ensues for several minutes. there is no possibility to edit. I don't seem to have any problem in AE, but I decided to use Pro Res capture to "do it right" because I heard that AE doesn't like HDV footage.

Should I NOT use ProRes for this project?

My system:
G5 Mac Pro 2x3ghz intel Quad Core, 7 GB ram, two internal drives with media on second drive. No sleep settings. OS 10.4.11

Thanks for any help on this!