The 48-Bit LBA support in Windows 2000 wasn't properly fixed until SP 3, and even then you needed to fix a registry setting:

48-Bit LBA Support for ATAPI Disk Drives in Windows 2000

Not sure if this related to external USB drives, but it'd be worth a shot.  If it does fix the problem I'd be very careful what other PCs/operating systems I connected to the drive with.

Thanks, I installed SP4 and hacked the registry according to MS - still no luck.  I found a driver that is needed from MS for the NEC USB 2.0 card.  That didn't help.  The only thing left to do is install the drivers that came with the USB 2.0 enclosure and I am not sure I want to do that - never heard of the company so I can't find any info on the software.