PS3 Advanced Options Problem - Product Details Not Displaying

Hi,

I seem to be having problems with adding advanced options to products. Please check Baron-Fire-Safe-with-Electric-Lock and you will see a safe that has 4 different model variations for the same series. The default model displays fine but as soon as you choose a different model from the dropdown details are not displayed - no image, no product title, price changes to '$.00', description dissappears and so on. Even if I then try to choose the first model again, details are not shown.

I've tried playing around with various options and I must be missing something very obvious.

I have had someone modify the files below for URL re-writes so I'm not sure if this is the problem...

/CSSMenuWriter/cssmw_home/menu.php
/.htaccess
/index.php
/Products_Detail.php
/Products_Results.php

If any of the above have caused the issue I'm guessing it would be the Products_Detail.php

Please help because I was very excited earlier today when I found out the URL re-writes are working very well - I'm an SEO person by trade.

Thanks,
Adam