phillip,
you're still making it too complicated! :)

i think you're getting confused by trying to combine directions from the perfect popup website, and zencart.

just follow my directions that i posted as my last post, namely:

1. DONT put the files in your "main_page" folder, follow the zencart directions here:

Any file in the includes/templates/{template_directory}/jscript/ directory with the following filename format will be loaded globally on every page of your shop:
jscript_{unique_name}.js
(where {unique_name} can be anything you want)
which means, change the two file names from:
add-event.js
popup.js

to:
jscript_add-event.js
jscript_popup.js

and add them to your "includes/templates/{template_directory}/jscript/ " folder

2. DONT use this on any page: (delete it!)
<script type="text/javascript" src="http://localhost/mainwebsite/includes/modules/pages/define_main_page/jscript_add-event.js"></script>
<script type="text/javascript" src="http://localhost/mainwebsite/includes/modules/pages/define_main_page/jscript_popup.js"></script>
it is not needed!

3. what you wrote as code for the actual link should be correct! just need to put the jscript files in the correct location, and disregard the code you put at the top of the page.

let me know how it goes!