These files can be recovered online if you look well enough...Try searching
http://www.dll-files.com/dllindex/ for these. I am running 98SE as well, so if ya can't find them, I can upload them to ya via IRC or mail.
Do you have a second hard-drive (I sure hope so)....You could copy files to that drive and then reinstall windows, depending on your particular configuration (I have a forced backup ready in case windows turns inside-out)...
I install windows on default, use a second drive for secondary installations [games, etc...], and a tertiary drive for archives. This way if windows goes "Tango Uniform", I can just wipe the C: drive and it makes for an easier reinstall overall....
Also, try "regcleaner". It's free and works quite well. You might also want to try getting "CCleaner" and using a memory-manager such as "Cacheman", since win98 is still bad with clearing unused random memory. Keep AVG updated, but this is most likely win98 just giving you grief for the fun of it...
If you can still find updates, get them right away, as this is the first and most essential step to solving problems with windows.