Replacing that code as posted brings site down when clicking 'New Topic'. Unable to handle request.

do I have to replace all of this

if(isset($_SESSION[$settings['session_prefix'].'user_type']) && $_SESSION[$settings['session_prefix'].'user_type']==2 && $settings['dont_reg_edit_by_admin']==1 || isset($_SESSION[$settings['session_prefix'].'user_type']) && $_SESSION[$settings['session_prefix'].'user_type']==1 && $settings['dont_reg_edit_by_mod']==1 || ($field['text']==$text && $field['subject']==$subject && ($field['user_id']>0 || $field['name']==$name && $field['location']==$location) && isset($_SESSION[$settings['session_prefix'].'user_type']) && ($_SESSION[$settings['session_prefix'].'user_type']==2 || $_SESSION[$settings['session_prefix'].'user_type']==1)))
        {
         // unnoticed editing for admins and mods
         $edited_query = 'edited';
         $edited_by_query = 'edited_by';
         $locked_query = 'locked';
        }
       elseif(isset($_SESSION[$settings['session_prefix'].'user_id']))
        {
         $edited_query = 'NOW()';
         $edited_by_query = intval($_SESSION[$settings['session_prefix'].'user_id']);
         $locked_query = 'locked';
        }
       else
        {
         $edited_query = 'NOW()';
         $edited_by_query = 0;
         $locked_query = $spam == 0 ? 'locked' : 1;
        }
 
       if($field['user_id']>0) // posting of a registered user edited
        {