Go back has saved me many times too! I think that ClamWin version .97 was not tested extensively on Win 98, althought it was tested. There are just not many beta testers, and hardly anyone has Win 98 now (care to volunteer for beta testing?), so there could be problems with a certain configuration, I guess. Another user reported a problem in the scanner forum before this one. Check it out and check Alch's answer.
Reinstall version .97 in case there was some glitch during your installation. If that doesn't work, uninstall it and try a completely new install of it. If that doesn't work, go back to the previous version of ClamWin and keep your eyes peeled here for developments. Older versions are available at http://sourceforge.net/projects/clamwin/files/clamwin/
on the web.
I think we are now at the point where if you have an older computer, you need to be involved in testing. You can't let someone else do it for you!