Yes, sorry. It probably was 3.2. :)
Yes, it was working fine before the upgrade.
I found the reason: I replaced these two lines from asyncjs.php
WORKING:
require __DIR__.'/async.js';
require __DIR__.'/fl.js';
NOT WORKING:
require __DIR__.'/'.$GLOBALS['_MAX']['CONF']['file']['asyncjsjs'];
require __DIR__.'/'.$GLOBALS['_MAX']['CONF']['file']['flash'];