All, Placed global search widget on my main homepage of my

Hi All,

Placed global search widget on my main homepage of my WordPress multi site. When I tried searching for a certain page title it cam up with the following:

Fatal error: Call to undefined function network_query_posts() in /home3/holmbury/public_html/holmbury.com/wp-content/plugins/global-site-search/global-site-search.php on line 262

Afterwards I tried again with another search term an the same thing happened. If there are any suggestions as to what's happened and if anyone could help me out it would be much appreciated.

Many Thanks

David