Hello Jan,
I have a different problem now.
A client told me when he orders a product and fills out the new customer form during checkout, when submitting he gets a blank page index.php
I checked and see this is indeed the problem, als on my front page there are product showing, if i click on the ADD TO CART button i als get to see a blank page with url index.php
Als i see strange urls if im on the page/category
www.thulefietsdragershop.nl/trekhaak.html
The links to the products link to example:
www.thulefietsdragershop.nl/accesoires/trekhaak/thule-euroclassic-g5-908.html
Whre does the accesoires come from? that is a different category.
What can cause this to happen?