Our version of the GA tracking code supports all the same basic functionality of Google's standard GA tracking code, though you won't be able to add optional extra functions that GA supports by adding parameters or other extra code to their standard tracking code.
Make sure to use our version of the GA code on every page of your site where you wish to use GA tracking at all (whether you have our Cart buttons on those pages or not), and do not mix-match our version of the GA code with Google's standard GA code or any other version of GA code, neither in the same page together nor across different pages.
I notice your "photoguides" page with E-junkie Cart buttons has two instances of standard GA code from Google, one up in the page HEAD and another at the end of the page, so you'd need to remove both of those. If your site happens to be using any plugins/add-ons (e.g., for WordPress or other such CMS platforms) that insert standard GA code in every page automatically, you'd need to remove/disable that.