HTL5 iFrame Not Working

I’ve created an iframe ad (300×250) and placed it on the right-hand side of the site, but instead of showing the ad, it’s iframing the site into itself.

It makes no sense, here is the iframe code:
<iframe src=”http://blackletterdesigns.com/wp-content/uploads/html5/taxes/taxes_300x250.html” width=”300″ height=”250″></iframe>

Here is the direct link to the ad that should be displayed:
http://blackletterdesigns.com/wp-content/uploads/html5/taxes/taxes_300x250.html

But it’s showing this site in the iframe:
https://www.telemundokc.com/

The page I need help with: [log in to see the link]