For the record, it seems that having a “clean install” of Snow Leopard may not matter. I did a clean install about a month ago, and am still having problems. FCP 7 was crashing a second or two after trying to start the program. Deleting prefs and repairing permissions didn’t help. However, after seeing some of the info on this forum, I created a new account, opened FCP 7 in the new account and started a new project. I saved the FCP project file to a common drive, and then logged back in to the old account and opened the FCP project file. It worked! Don’t know if it will help anyone else, but for now it’s working for me.
-Jerry Hartman