Hi. 3.0 ran fine on my Win 98SE computer, and I have lots of hard disk space (a shortage of which can be the cause of this error). I followed the disable and uninstall instructions for 3.0. Two files were left in the folder after uninstall. The first time I installed 3.1, I left them there, second try I deleted them and the folder. Same error message when trying to start up 3.1. Also registry problems according to Norton WinDoctor after uninstalling 3.0, one was invalid shortcut and two unidentifiable ones which may or may not be related. Thinking it was a corrupt download, I got 3.1 from another of the locations listed, same result.