Excel save file problem

I have a client (new Office 2000 install)trying to save a file done origanally in Excel 97 and saved to a network drive running 4.11. It will allow her to save it the first time but anytime after that it tells her that it “could not rename the file”and saves it to a temporary file, telling her to open it and rename it. I tried to edit and save it from my PC which also has Office 2000 and had the same problem. The file was not protected so that is not the problem. Any ideas?