Posts unreadable, they are broader than the screen??

What went wrong? I have chosen the free version of catch box and installed a layout with a header and two columns. My postings appear in the right column, but they are broader than the column and are not readable, because the text falls off of the screen. I saw it in safari as well in chrome, did not test other browsers. What went wrong?? my site: www.astacus.nl (sorry, it's a Dutch site) Greetings, Cor