One thing that seems to cause an exceptional amount of problems with using ZenMagick seems to be zen-cart’s missing page check. This check, which is enabled in a default installation, validates all requests. If no zen-cart template file found that corresponds to the value of main_page, the homepage will be displayed (via a redirect).

Since ZenMagick is using a number of custom page names, for example static for define pages, define pages will not work as expected if the check is enabled. Another example are the Ajax requests.

So, when using ZenMagick it is important to disable this feature. The setting  can be found under admin: Configuration -> My Store