Ok, got a really strange one here I think, I haven't come across it before, although I am awake over 30 hours so I could be missing something really silly now.
Anywho go to this section of the problem site with internet explorer: http://tinyurl.com/5pzweg and try and filter the results. (Just click free trial for instance) - It doesn't work at all for me and I haven't a clue what's happening. But if you use firefox, it works fine.
PHP shouldn't care what browser you use, I just don't get it .
Have any of you ever come across something like this before??