Have you tried re-running setup?
If you get this error every time you run setup, my first thought is that you have a bad W98 CD.
If you get other errors, you might have a memory problem.
(Just went through this myself.)
I have found that many DIMM modules will make it through the POST memory test, yet not function properly under Windows.
I just replaced a no-name DIMM with a Kingston to correct W98 loading problems on a Slot A system.
This kind of problem is most common with older motherboards and new RAM modules.
The SDRAM DIMM standard is a non-standard in my opinion.
There are just too many instances of DIMMs that do not work with some motherboards.
Chas