eCommerce theme breaks wordpress

I have tried using multiple WordPress 3.x installations, but I as still having issues. I can install the eCommerce theme fine, it is just activating it that is the problem. When I activate the theme, the whole thing crashes. Front end, back end, and to fix it, I have to change the theme folder name on the server to something else, then it is fixed, but it reverts back to the old theme. It will work on any other theme besides an eCommerce one.