I think that the best chances are that Win98 is nolonger supported, maybe by the installer itself or windows installer. I think neither MS doesn't support Win98 any more.
EDIT:
maybe is DirectX who is responsible !!! I think you need at least DirectX7 and Win98
AFAIK has only 6.4 or someting like this.
EDIT2:
Unofficialy this support does not exist any more.
Officialy:
Effective July 11, 2006, Windows 98, Windows 98 Second Edition, and Windows Me (and their related components) will transition to a non-supported status. After this date, Microsoft will no longer provide any incident support options or security updates. Microsoft is not offering a custom support agreement for these products.
http://www.microsoft.com/Windows98/