AD logins only after reboot

10.4 server 10.5 client AD server is server 2008 After a reboot on the client I can log into any account on the AD and the network home mounts and everything is good. Problem is on log out the next user gets"you cannot log into this account at this time" error. Until I reboot. Any clues as to where to look to troubleshoot this one? dsconfigad -show all looks fine, time is synced, server shares are good, I am only using the AD for authentication and an xServe for the SMB file service. NFS is not running on the server but in WGM under users I see NFS shares turn up (although grey) randomly. I plan to use another server for machine management but have not set this up yet. Help much appreciated Carl