open search.php, line ~685:
Replace
Code:
if ( intval($search_id) )
{
$sql = "SELECT search_array
FROM " . SEARCH_TABLE . "
WHERE search_id = $search_id
AND session_id = '". $userdata['session_id'] . "'";
with
Code:
$search_id = intval($search_id);
if ( $search_id )
{
$sql = "SELECT search_array
FROM " . SEARCH_TABLE . "
WHERE search_id = $search_id
AND session_id = '". $userdata['session_id'] . "'";
Info from a trusted source, phpbbs own site:
http://www.phpbb.com/phpBB/viewtopic.php?f=14&t=153818