JulienMWS

In mcsw.php, before this code
if (!empty($_POST['wpmm']))
put this code :

$languages = icl_get_languages('skip_missing=0&orderby=code');
    if(!empty($languages)){
        foreach($languages as $l){
            if ($l['active'] == 1 && $l['language_code'] != 'fr') { // fr is default langage, remplace by YOUR default langage
				$la_langue = '?lang='.$l['language_code'] ;
			}
        }
    }

then, replace this code :

if (get_option('permalink_structure')!= '')
          {
              wp_redirect(get_bloginfo('url').'/categories/'.$sql.'/search_type/'.$_POST['mmctype'].'/order/'.$_POST['order'].'/');
                  exit();
          }
          else
          {
              wp_redirect(get_bloginfo('url').'/?cat='.$sql.'&search_type='.$_POST['mmctype'].'&order='.$_POST['order']);
                  exit();
          }

by this one :

if (get_option('permalink_structure')!= '')
          {
              wp_redirect(get_bloginfo('url').'/categories/'.$sql.'/search_type/'.$_POST['mmctype'].'/order/'.$_POST['order'].'/'.$la_langue.'/');
                  exit();
          }
          else
          {
              wp_redirect(get_bloginfo('url').'/?cat='.$sql.'&search_type='.$_POST['mmctype'].'&order='.$_POST['order'].'&'.$la_langue);
                  exit();
          }