That happens when the partition or the HDD runs out of space. Also, if you are saving to a network, and the network source gets shut off or interuppted, you'll get these messages too. Could also be a sign of your HDD going bad, although most newer drives have technology built in to warn you off this (S.M.A.R.T)
Who's the manufacturer of your HDD, when did you buy it? Did you do a CHKDSK?
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS