how can get customer's entity groups?

Hi,

I am trying to get Customer's groups. This filter is not working, getting [Error]: [Code=INVALID_KEY_OR_REF] The specified key is invalid.

Can someone help me to filter out only Customer's entity groups?


   EntityGroupSearch groupSearch = new EntityGroupSearch();
   EntityGroupSearchBasic groupSearchBasic = new EntityGroupSearchBasic();

    //getting groups of type (customer)
      SearchMultiSelectField groupType = new SearchMultiSelectField();

       RecordRef[] types = new RecordRef[1];
       types[0] = new RecordRef();
       types[0].setType(RecordType.customer);

       groupType.setOperator(SearchMultiSelectFieldOperator.anyOf);
       groupType.setSearchValue(types);
       groupSearch.setBasic(groupSearchBasic);

      SearchResult result = _port.search(groupSearch);


Thanks,
Babar