is_submit is undefined error

[zenrei]

Your phpBB Version: 2.0.22
phpBB Type: phpBB / IMPortal
MODs: Yes
Your knowledge: Basic Knowledge
Board URL: http://falloutzone.net

PHP Version:
MySQL Version:


What was done before the problem appeared?
upgraded to 141 from 140


What was done to try to solve the problem?
nothing yet



De.scription and Message

when i'm submitting a reply, i get the IE error:

Line: 720
Char: 12
Error: 'is_submit' is undefined
Code: 0
URL: http://falloutzone.net/fos/posting.php? ... ply&t=3310

I see that someone got this same exact error in 140 as well, but no one replied to his post.

How do i get rid of this error?