In short, Network Solution Image Cafe currently does not support adding your HTML using Internet Explorer.
For some reason, other HTML may or may not be added properly, but Opentracker.net's script is definitely not.
The current solution is to use Mozilla Firefox browser, which can be downloaded for free.
If you enter Image Cafe from Network Solutions website, once you visited using Mozilla Firefox, then the HTML can be added.
Please note that Firefox does not necessarily fully support Image Cafe other functions. However, I used it for adding your HTML only, and it worked fine.
You should finally be able to track properly with this fix.