Apple – Support – Discussions – Update to 10.6.6 Frozen at Blue Screen …. Turns out that it could be either a failing hard drive, or an external drive that is attached to the computer. Disconnect any external Hard drives and restart the computer.
Now you should see your external drive at the bottom of the Project Library List view. Hold down the Command Key while dragging the small icon for your project to the small icon for the external drive.
Now, with the Project still selected, click FILE/CONSOLIDATE Media… and you can move over the Events, Music, and Photos for the project to the external drive as well.
Plug this drive in to the other Mac and you are ready to edit.