Won’t Read HTML?

I am trying to place an article with copyright restrictions into a blog post… I have to use their HTML code to use their ads etc.
When I enter the code in HTML part, then go to Visual, it appears like it should.
When I go to preview, only the text of the code displays.
Any assistance would be of help. Here is the code..

<SPAN
STYLE="position:absolute;
width:300;
height:500;">
<IFRAME
SRC="http://license.icopyright.net/user/viewFreeUse.act?fuid=ODkyNjc1OQ=="
WIDTH="300"
HEIGHT="500"
MARGINWIDTH=10
MARGINHEIGHT=10
FRAMEBORDER="NO"
SCROLLING="YES"
STYLE="border-width:1;
border-color:#000000;
border-style:solid;"
>
</IFRAME>
</SPAN>