I fixed this issue by overriding the IsAdministrator function:
Public Overrides Function IsAdministrator(ByVal userid As String) As Boolean
Dim userGUID As Guid = New Guid(userid)
Dim LoginName As String = Membership.GetUser(userGUID).UserName
Dim IsUserInRole As Boolean = Roles.IsUserInRole(LoginName, "ChatAdmin")
If IsUserInRole Then
Return True
Else
Return False
End If
End Function
Hope this helps.