I would appreciate help with the following issue:

I have created a local group in our SQL 2008 server and added two Windows
user accounts "DOMAIN\UserName" I then added the local group to the
database and granted read only access.

The users are trying to link tables using MS Access using and ODBC
connection and getting the following error.
Users are not system administrators.

Date 6/30/2010 1:01:54 PM
Log SQL Server (Current - 6/30/2010 1:10:00 PM)
Source Logon
Message
Login failed for user 'DOMAIN\UserName'. Reason: Token-based server access
validation failed with an infrastructure error. Check for previous errors.
[CLIENT: 999.99.9.99]

Date 6/30/2010 1:01:54 PM
Log SQL Server (Current - 7/1/2010 8:12:00 AM)

Source Logon

Message
Error: 18456, Severity: 14, State: 11.

Database Server:
windows Server 2008 R2 Enterprise
System type: 64-bit Operating System
SQL Server 2008