rblanda - since you mentioned the SSL plugin, I assume you use DT Register. Are you using DT Donate also or did you just post in the wrong forum category? You can not use the SSL plugin AND this code added in your template. The plugin is for DT Register... it will not make DT Donate secure. If you are using both, you need to forget the plugin and use the code inserted in your template.
The IE secure/non-secure warning has nothing to due with this code or our plugin. That means you have some items on your site that are loading from hard-coded NON-secure locations in the midst of a page that is trying to load securely. This is almost always tracked back to your template. Could also be some other plugin/module on the page. Anything that is pulling in an image, css file, javascript, etc. Everything must be relative, no absolute non-secure links.
My guess is you don't have a SSL certificate properly setup for your site. You need a dedicated certificate, not a shared one. If you DO have a SSL cert setup and can't sort this out, submit a ticket with site access.