I get a 'Site Untrusted' When I add to our cart. Here's a screenshot of what I get: http://grab.by/3zhP This is the text of the warning.
This Connection is Untrusted You have asked Firefox to connect securely to promostadium.com, but we can't confirm that your connection is secure. Normally, when you try to connect securely, sites will present trusted identification to prove that you are going to the right place. However, this site's identity can't be verified.