What are the machine specifics? I think I got this error when I tried registering the KixGUI.dll on a Win 9x machine that did NOT have the VB5 runtime files installed. I could be mistaken, but it was a message very similar to this.

Don't believe the documentation that says that only Office 97 is required because that isn't necessarily true. I found that in some instances the Office 97 didn't install the VB5 runtimes.