Iíve configured an Ldap authentication source. The Ldap server is on

I populated the ďAdvanced Active Directory/LDAP Configuration as it :

User ObjectClass: inetOrgPerson
All Users Filter: (objectclass=person)
User Relative DN Attribute: cn
Group ObjectClass: groupOfNames
All Groups Filter: objectclass=groupOfnames
Group Relative DN Attribute: cn
Group Membership Attribute: member

When I try to add a group I notice that there is a comma just after the
group name (is that normal?).I add my group then I click Next, next,Ö and
get this error

ďAn error occurred while fetching Active Directory/LDAP group membership:
E_ADS_UNKNOWN_OBJECT: An unknown ADSI object was requested., hr 80005004Ē

so ??