[johnmont]

I had to do this for 3.5.4 -- its also apparently good practice to add intval to the condition....

REPLACE by:

PHP Code:

// Start hack MarcoH64 
if (is_array($user['usergroupid']) OR is_array($user['membergroupids'])) 
    { // for emails 
        if (is_array($user['usergroupid'])) 
        { 
            foreach($user['usergroupid'] AS $id) 
            { 
                $u_condition[] = "{$prefix}usergroupid = " . intval($id);
            } 
        } 
        if (is_array($user['membergroupids'])) 
        { 
            foreach($user['membergroupids'] AS $id) 
            { 
                $u_condition[] = "FIND_IN_SET('" . intval($id) . "', {$prefix}membergroupids)";
            } 
        } 
// End hack MarcoH64