Have you run any other USB devices - before using USB for anything "serious" like a scanner, printer or CD-ROM/RW, I'd advise buying a cheapo USB mouse, just to make sure the USB subsystem is functional.
Another thought - a drive of that speed needs USB 2 - at least for full performance - if it runs at all in USB 1, performance will be severely restricted.
We ARE assuming that this IS a USB external drive, otherwise USB is a complete red herring ?????
If it's a desktop and not a laptop, then fitting a USB 2 PCI card (make sure it has drivers with it!) may be required.
Win98 (non-SE) is a little fraught for USB compatibility though - there may be some updates that help, but it's no the relatively safe bet that 98SE is.
PS. Another "rule of thumb" is to avoid putting fast or fussy devices through a USB HUB (unless they draw power from the USB, when using a powered hub often improves things)