I get the same problem from time to time, if I close down and start up again it seems to work OK. You have win xp so if you have a problem with memory it tries to automatically allocate virtual memory. Sometimes I can render an image at 4060 with 300dpi no problem. Then straight after I try 2048 x 1536 at 300dpi and get the problem occur. I save and close, re-open and try again and it works. It is a right royal pain in the ass but I don't seem to get the problem again with that file.