Active Directory/LDAP :: Getting User Groups / Can't Use UserPrincipal.GetGroups In System

I am having trouble using UserPrincipal.GetGroups in System.DirectoryServices.AccountManagement.

When I use the following code:

PrincipalSearchResult<Principal> groups = userPrincipal.GetGroups();

foreach (GroupPrincipal g in groups){
Console.WriteLine(g.DisplayName);
}

I get the error "The value for the property AttributeScopeQuery cannot be set" in the foreach loop. I also get the same error when using groups.Count()I have read things that indicate this may be due to having some Windows 2000 domain controllers in the domain and so meaning it does not support ASQ.

What is the best way of doing this? The best I have come up with, since most of the rest of my code is running fine using System.DirectoryServices.AccountManagement is using the GetUnderlyingObject method of the UserPrincipal to get a DirectoryEntry and enumerating the values of the memberOf attribute. Using LINQ the code is quite compact:

var groups = from string groupPath in
((DirectoryEntry)userPrincipal.GetUnderlyingObject()).Properties["memberOf"]
select new DirectoryEntry("LDAP://" + groupPath).Name.Replace("CN=", "");
foreach(groupName in groups){
Console.WriteLine(groupName);
}