In order to be able to add HealCode Widget code to an Adobe Contribute site, the site administrator needs to enable access to Allow HTML Snippet Insertion to the site in the Publisher Settings.
Once this has been enabled, a new feature in the page editor will be enabled that allows you to paste your HealCode Widget code.
Here is the corresponding document on Adobe's help site for Contribute:
This is normal. Just preview your page in a normal web browser such as Firefox, Sarafi, or Google Chrome and the page should display properly.