Files are "Read Only" for Windows 2000 Users

[ Posting for Matt Corippo ] Whenever Win2000 users open a doc in their group, the doc opens "read only" on our Mac OS X Server 10.1.4 G4. The owner and group privileges are set to R/W, and everyone is set to --. If I click the "copy privileges to all enclosed items" button, then the Win2000 user can open and modify a doc once, then it is read only again. I am unable to change the privileges on the 2000 side. I have read this is a known issue, but have not found a fix yet. Can anybody point a newbie in the right direction? And does Mac OS X Server 10.2 make this mess go away?