Problems with AD Windows users

Hi, we have tried to get a Xserve to co-operate with Active Directory, but have run into a problem. First of all we installed a test server. Made the configurations in the DNS, bound it to active directory, put the Xserve as a WINS client, started the Windows services. Everything worked as expected. Windows users could double-click the Xservers icon and were logged in automatically. Mac users could log in via AFP or SMB without problems The we made a clean 10.3 install on the xserve and configured it in exactly the same way, except for ip and name. (Btw all names are in small letters). Logging in from a Mac works ok (via AFP and SMB) but trying to log in from a Windows machine that is part of AD gives this error: \\xserve is not accessible. The account is not authorized to log in from this station. (xserve is the name of the server) Logging in from the same Windows machine using ip number works without problems. But using \\xserve or \\xserve.domain.com give the same error. Any ideas what might be the problem? Tycho