Error using Search builder for contacts with no gender set (4.4.4 starterkit)

[tv2011]

Hi, I'm trying to search through contacts by using the Search Builder. If I create a search for contacts where Gender IS EMPTY, the search runs but I get this error:

Code: [Select]

Notice: Undefined index: in CRM_Contact_BAO_Query->optionValueQuery() (line 5080 of /srv/domain.tld/public/htdocs/profiles/civicrm_starterkit/modules/civicrm/CRM/Contact/BAO/Query.php).

Any idea how I can fix this?