bans.php: surpress error

inc/bans.php

@@ -181,7 +181,7 @@ class Bans {
 				$ban['username'] = '?';				
 			}
 			if ($filter_ips || ($board_access !== false && !in_array($ban['board'], $board_access))) {
-				list($ban['mask'], $subnet) = explode("/", $ban['mask']);
+				@list($ban['mask'], $subnet) = explode("/", $ban['mask']);
 				$ban['mask'] = preg_split("/[\.:]/", $ban['mask']);
 				$ban['mask'] = array_slice($ban['mask'], 0, 2);
 				$ban['mask'] = implode(".", $ban['mask']);