Did you try using this code example from the manual?

Code:
$Index = 0
DO
    $Group = ENUMGROUP($Index)
    $Index = $Index + 1
    ? $Group
UNTIL Len($Group) = 0


Or if you know the LDAP path you could do something similar to this:

Code:
Break On
Dim $SO
$SO=SetOption('Explicit','On')
$SO=SetOption('NoVarsInStrings','On')
 
Dim $User,$Group
$User = GetObject('LDAP://CN=John\, Doe G.,OU=Users,OU=Finance,OU=WEST,DC=MyCompany,DC=com')
? 'Getting object err was: ' + @ERROR + '  ' + @SERROR
For Each $Group in  $User.groups
;	? Join(Split($Group.name,"CN="),"")
;	? $Group.SamAccountName
;	? $Group.name
	? $Group.adspath
Next


As Howard mentioned you need to add some error codes if you have problems returning the expected data so that you can determine why.