Access Denied - LDAP Provider

[snakeeyes1978]

In Active Directory I create a Query-Based Distribution Group and add the members. When I edit the properties of the group and go to the "Exchange General" tab and try and set message restrictions so that only two users can send to the list it comes up with this message:

Access denied.

Facility: LDAP Provider
ID no: 8007005
Microsoft Active Directory - Exchange Extension

I have searched the web and can't find any solution. Everything points to a hotfix in Exchange 2003 SP2 but I am already running SP2.

Any ideas?

 

[snakeeyes1978]

To add to that, even simply changing the Display Name on that page gives the same error - I'm lost.