Time Machine fails to back up.
I get this error message when backing up about half-way through a 440 GB back-up: "Unable to complete backup. An error occurred while copying files to the backup volume." I've tried restarting but it failed again half-way through. Any help would be appreciated. I've deleted the old backups folder each time and emptied the trash, so each time has been a new back up.
MacBook, Mac OS X (10.5.8), Backing up onto a WD 2 TB HD