Problem solved. Thank you very much!
The problem is caused by the HT Mega Plugin. I don’t know why or how, but it reverses your column counter. Instead of 0 to 1 to 2 … it makes a different operation: 0-x while x is the number of posts. I don’t know why, if you already know the problem please tell me I’d be very interested!
Nevertheless I thank you very much and am thanks to you now nearly ready to publish our new website.
Thanks!