I created a stand alone AD LDS instance using the setup wizard.  Then I used ADSI Edit to create a Users container.  Next I created a user, set the password and set MsDS_UserAccount Disabled to False. Then I tried to expand Roles, Expand the Readers, edit the member property and Add DN: o=Microsoft,c=us,CN=Users,CN=Joe and I get the following error:

Operation failed. Error code: 0x20b5 The name reference is invalid.  Problem 1005....
How do I fix this?  Also can't a user just be defined in AD LDS or is it just a reference to a real windows account?

Thanks