in reply to Copying a large file (6Gigs) across the network and deleting it at source location

robocopy is well suited for this. I've used it for a lot of large (read: 20-50 gig) data migrations and it's worked fairly well. It has a switch to retry on errors, and it can recover from network glitches. You can also copy security info. It's in the NT resource kit, and I believe it comes with XP.