[Koha] analytics

Dear friends, I want to activate Analytics feature in our system. So, I have set the system preference UseControlNumber to Use. Then, I have edited the Child record (i.e. made the host item entries in the field 773) and it worked.  However, when I passed to the Parent record, something went wrong. I have filled the 774 field (child's control number in w and title in t). As a result, Analytics: Show Analytics appeared on the record, But when I follow the link, no result is found.  In the search box I have the query "rcn:000502577 and (bib-level:a or bib-level:b)". Any suggestions? regards, haik.