Backward compatabilty for Win98

I developed a Windows GUI software with Visual Studio 6.0 under Win2000
professional. It worked fine with any edition of Windows 2000 and Windows
XP. However, when I ran it on a Win98 machine, I got the following error
messages:
"Debug Assertion Failed! ...
File: auxdata.cpp
Line: 83".
Does anybody know what happened here? Could anybody please let me know how
to develop a piece of software on a Win2000 desktop but also supports Win98?
Thanks in advance.
Johnson