strange problem connection to smb - "net use" works "Windows Explorer" doesn't

I am a newbie at Linux, but I have some how managed to setup a samba domain member server.
The server will be used as a fax server.
Installed hylafax and smbfax and everything is working well.
Connected to the domain no problem using security=ads.
Kinit, wbinfo -u, getent all work no problem.
However, there is one strange problem when attempting to connect from an XP box. First I must connect using:
"net use * \\SMBServer\Share /USER:domain\user"
only THEN can I access the share through Windows Explorer????????
Has anyone ever come across this problem?

Thanks for any help!