Well, first off, you made a mistake getting that enclosure most likely. It probably uses the Oxford900 chipset. And since you threw stuff away, you can't return it. In the future, order online and make sure the enclosure uses the Oxford911 chipset. It provides double the throughput. I made the same mistake with my first purchase, just because I didn't want to wait for shipping. Buying online is also nearly half the price.
You can look at the chip to verify which one it uses, but it probably is the 900 because it's cheap to use.
Win2k should work immediately with a Firewire enclosure. The Oxford chip provides a standard interface which is Plug N Play, no extra drivers are needed. The drive itself will just show up as a device connected through the Oxford chip.
Once you have the drive plugged in, you may need to reboot the first time. Then look in Device manager and you should see an SBP2 Compliant IEEE 1394 device listed. Then under the Disk Drives list it will show an Oxford Semiconductor device (Windows can only see the controller chip, not the type of drive used).
After that you may need to initialize the disk in Disk Management, in the Computer Management console (Administrative Tools) and partition and format it.