Fix php-warning in the modules menu of oscommerce

When browsing to the modules menu of an oscommerce website (v2.2 rc1), there are a lot of erros/warnings showing up. See screenshot. I noticed them after uploading a new payment module i wanted to configure. The new payment module shows up in the warning messages, so i'm unable to configure it. The site itself does work and the 2 existing payment methods are also working. No need to change that. Need this fixed today or tomorrow.