What release/service pack of VB? What release/service pack of Windoze-98? Especially if that is the first edition (gold) of 98, it can be REALLY tempermental about VB.NET packages, even if the .NET runtime has been appplied.
Can you include any screenshots of error messages?
I've seen some peculiar issues with the Visual Studio 6 deployment tools when they are run on an XP machine. Is there an easy way to rebuild your package on either a 98 SE machine or a Win-2000 machine?
usually setup ask to restart when setup is trying to update msvbvm60.dll and msvcrt.dll.
Check those files are not readonly and close any programms that uses those files and try again.
If all fails get vb6sp5runtime from microsoft and install before installing your program.
OK, without msvbvm60.dll and msvcrt.dll the installation proceeds and it works (it does prompt that some new files may threaten system stability). But the computer have visual basic on it. Will a computer without VB run it too without those files in the installation?