File sharing between W2K and Millenium

One of our clients has a non-server based star network in place with 2 workgroups in effect (“Ettrick Dev” and “BRP”).
There is 1 computer in the “Ettrick Dev” workgroup running Windows Millenium. There are 5 computers in the “BRP” workgroup running W2K.
The problem arises when the Millenium computer attempts to access files stored on one of the W2K computers. The network password prompt appears (Origin $IPC) and can go no further from this point.
There is nothing special about the W2K systems, however they are formatted with NTFS.

I am only just starting out supporting W2K and Millenium so any help would be greatly appreciated with enabling file/printer sharing between the 2 workgroups.