I am only using the product info page and following functions in Zencart. When I access the product info page I receive a blank screen. I had MSU working at one point. The issue I had at that time was Zencart would only add 1 Item to the add to cart page. The url of the product info page was shortened properly. The add to cart page url had the dynamic url information in it. I tried to load the original zencart files into a later version & that is when I receive a blank product info page. I also tried to run the activation function & that page came up blank. Trying to create a new htaccess file also did not work. When I disable the MSU function the product info page works properly as well as the add to cart function ( adding multiple products). Msu is installed in the following site:
http://www.anthonysbabyboutique.com/Zencart/