I had this same problem with my PowerBook 2400c and 8.5.1. The only way I could get it to work, after several other attempts, was to reformat the HD. Actually, you may want to try a clean install on 8.5. That may work before you go formatting it. Then reinstall Office. Surprisingly enough, it worked after that. I don't know why. It's one of those Microsoft things I guess. The funny thing was, it works perfectly fine on my G3 desktop and G3 PowerBook. Also, my 8500 and G3 minitower. No problems with those. All using 8.5.1 and Office 4.2.1a. Just the 2400c one time. Hope this helps a little.