CompuServe Messages

Please Help: I'm having a problem when rendering flics. For example, on a 300 frame flic when the computer gets to frame 187 or 165 or any frame above the half way mark the system stops rendering and displays the following " WRITE ERROR TGA FILE 187" . It then asks me if I want to go through the color converting process. After I select yes it wil do so untill it gets to the last frame. It will the say "TGA FILE 00187.TGA. IS CORRUPTED". It then reverts to the key framer ,and I end up with 187 separate targa files. What is a "corrupted" file? What is the problem my computer or the software? This happens even when I use Pideo Post to organize the separate targas into a flic. Please help me this is getting extremely frustrating. Thank You in advance ;