System runs fine otherwise, but the two USB 1.1 ports on the mobo's back I/O panel refuse to work.

Win98 device manager doesn't show any errors in principle:

But when I plug in an USB pendrive it asks for "new drivers for Mass Storage Device":

Then apparently it can find anything of the kind on the Win98 installation CD ???:

Am I missing something? Are some extra drivers from elsewhere needed?

Any help would be appreciated!