if I remember correctly, the toggle for the USB ports should be under 'chipset <something>' in the bios. It's there though, under one of the menus, in the original bios. You should then enable USB, and win98 will detect it upon bootup. However, on my configuration, when win98 would try and install the driver for USB, my machine would lock up. I upgraded my bios to the original OEM bios found in Misfit's bios pack, available here:
instructions on flashing your bios are included.
After upgrading my bios, the USB driver installed without a hitch.
However, my USB ethernet adapter never fully worked correctly (at least using the Compaq USB Host Adapter driver)
Let us know how your USB device works for you...
Also, to fix the PCI Bridge conflict/problem/annoying ! symbol :)
I would eliminate the audio and graphics drivers from the installation list, as I've heard of people having problems installing the complete package.
Just install the video/audio drivers seperately... if you didn't know, they can be found here:
good luck, and make sure to update us!