Welcome and thanks for the kind words.
Also thanks for providing the link.
I've tested the page in question in IE9 and Ninja Shadowbox works fine.
However, in IE7 and IE8 it didn't work as expected.
What you can try is the following:
Open the index.php file of your default template.
Paste the following code right after the opening <head> tag
(make sure it comes first):
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9">
<http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9">
This piece of code makes your website run in IE7, 8 and 9 compatibility mode. This affects only IE browsers.
I hope this helps.
Let us know how it goes.