You've probably resolved this but I am replying in case someone else searches this.
The issue is almost certainly Quicktime. I just went through this nightmare for a whole weekend as I was trying to consolidate data from several old hard drives. Quicktime CODEC's access *every damn time* you touch the file *IN ANY WAY*. This means that if you have a corrupt codec or an issue with Quicktime it will prevent you from deleting the file OR DIRECTORY that a .MOV file is in. Remove Quicktime, iTunes and any other Apple product that might use the CODEC from your system and you will be okay. You can then reinstall them fresh (remember to save your registration codes before you uninstall).
EggHeadCafe - .NET Developer Portal of Choice
http://www.eggheadcafe.com