Network Home Directory can Bind, but cannot login

We are currently testing 10.4.1 on an iBook and have a problem connecting to a Windows 2003 Server through Active Directory (using the AD plugin) and mounting a users Network Home Directory. I am able to bind the computer account in AD, but I cannot login in with a user that has a NHD on the Windows 2003 Server. I can login in locally and manually mount the share, as well as other shares on the server. I have successfully configuring the AD plugin on other 10.3.9 machines and authentication is not a problem. SMB is working, DNS is able to resolve names, and I can bind computer accounts. Basically I can authenticate manually after I've logged in locally, I just can't login with a domain account that has a NHD. Both a standard user account and admin account (no NHD) works just fine. Any ideas what might be the issue? Why does a client running 10.4.1 not work when the exact same account on a 10.3.9 machine work fine?