Wierd Large Photo Issue

I have the weirdest issue. In Firefox or Safari, clicking the view the large version of a product detail image works fine. In Internet Explorer 6/7, the popup window opens, but the stores home page is displayed.

I’m using SEO links, so my product page is /cscart/mens/shirts/patch-tee.html. Firefox and Safari link to the image.php file to display the large image from /cscart/ where IE6/7 links to the image.php file from within /cscart/mens/shirts/, which doesn’t exist.

Any ideas?

In the fn_pop_img() function, I added {$smarty.const.CSCART_HOST_DIR} before the image.php link.