This issue has to be so easy I know I will hate myself when someone pops up with the answer.
Our school system has one forest with 8 domains. One domain for the Admins and one each for the various schools... Don’t ask why, we inherited it.

The issue is that if a user from any of the School domains logs onto any computer in the forest they get all their drive mappings; all well and good. But if a user from the Admin domain logs onto any computer other than an admin domain computer they will not get their drive mappings. If the user browses to the NETLOGON share and runs the script manually the drives are mapped.

Here is our setup:
Windows 2003 domain controllers.
Windows XP and Windows 7 Clients

Top level domain = forest.org
Admin domain = aaa.org
School domain = bbb.org

*Drive mappings for users of the aaa.org domain are called from batch files (C:\WINDOWS\SYSVOL\sysvol) entered directly into the logon script field of the profile tab of the users AD account. We also attempted to put the specific UNC path in the Profile path field of the AD account.
*Drive mappings for users of the bbb.org domain are called from batch files in a GPO logon script.


User from aaa.org logs onto bbb.org the script, net use f: \\server.aaa.forest.org\users\%username% does not map the drive. Running the script manually works fine.

User from bbb.org logs onto aaa.org the script, net use h: \\server.bbb.forest.org\users\teachers\%username% does successfully map the drive.