Either you don't have permissions or the RIDMaster FSMO role holder is unavailable to create new relative identifiers
1.Open Active Directory Users and Computers.
2.Right-click the domain node, and then click Operations Masters.
3.On the RID tab, under Operations masters, view the current RID master.
Check that its available - if not bring it back on line
Last Wiki Answer Submitted: April 12, 2010 3:31 pm by Richard Siddaway2,260 pts.
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Could you please post the complete error message and provide more details about the situation and your environment ?
Thanks.
Also, as relative identifiers are mentioned, you could use the Dcdiag tool to test the RidManager.
The command would be something like this: