There is an odd issue on your index page. If you add any url parameters it won't load. I couldn't figure out the cause, but I added code to make sure all url parameters are removed if it redirects to the index page.
You can see the issue by visiting:
It shouldn't cause an error adding a ? to a url, but it seems to just on your index page. Maybe your server administrator could debug why that happens, but I've fixed the problem with a work around that prevents any url parameters from being added to the index page redirect.