Read something about Javascript access security here:

• http://javascript.about.com/od/reference/a/frame3.htm


• Unsafe JavaScript attempt to access frame warning in Safari


• "Unsafe JavaScript attempt to access frame with URL..." error being continuously generated in Chrome webkit inspector


• http://blog.chromium.org/2008/12/security-in-depth-local-web-pages.html

Specifically about implementing Vimeo and JavaScript unsafe access, I found this on a discussion on the Vimeo forums:

If you're using a webkit browser (Safari or Chrome) that error is
actually coming from the Webkit Inspector trying to access the iframe
(the Webkit Inspector is actually written in HTML and Javascript).

The
thing to make sure is that you can't call any of the api or addEvent
methods on the iframe until the player has finished loading. As per
the example, you need to add the onLoad event first and then execute
your code inside of that handler.

And second, I checked link you provided, and it loads fast and fine to me, so it is definitely not reason why you keep having this page loading long time