I just purchased a Linksys EFG250 NAS device and am getting identical behavior. I can do a couple of backups and then they start failing with an Error 1100. I am backing up to 37 different backup sets whose sizes range from 1 to 12 gigabytes. Two sets started to fail with the 1100 error (a 4gig and a 7 gig set). I had been using an earlier model of the Linksys NAS device with 80 gig hard drives. It always functioned very well for me using the same backup parameters.