Currently Being ModeratedFeb 9, 2013 6:14 AM (in response to Niklas Wikman)
by any chance, is your scratch disk formatted as anything but macosextended? if it is, reformat or replace with a macosextended drive.
If that's not the issue, I have no idea what's going on, but here's how I would proceed.
first, try deleting your fcp preferences
And here are a bunch of fcp troubleshooting steps.