I think we're already working with you on this via email, but the issue is that you're forcing your entire site to load with https: URLs rather than the standard http: URLs, and our standard button codes provide http: URLs for the button image and box.js View Cart script that manages the overlay-style cart display "inside" your page. If you prefer to keep your entire site loading as https: for some reason, simply change all instances of "http:" to "https:" in the E-junkie button codes you have pasted into your pages.
That said, the only reason for using a secure-encrypted (https:) URL is when sensitive personal or financial information (such as a credit card account number or a login password) is being transmitted to or from the buyer's browser, as https: ensures such transmissions will be SSL-encrypted in case of potential interception by any third party. This is entirely unrelated to the security of your site/server in terms of its resistance to hacker intrusion.
All E-junkie cart orders in progress are anonymous until checkout, so there's little point in using https: before that point. It also slows down page-load performance, due to the overhead of encrypting every page before it's sent to the buyer's browser, which then needs to decrypt the page before it can be displayed. The nature of our service eliminates any need for our sellers to implement https:/SSL encryption security on their own sites, as we automatically take care of the transition to checkout using https: for you when necessary.