Putting an iframe in a post?

When I try to insert an iframe from amazon.com affiliates into a post, the sidebar dissappears entirely. Here is the code I am inserting:

<iframe src=”http://rcm.amazon.com/e/cm?t=httpwwwclassi-20&o=1&p=8&l=as1&asins=B00006879E&fc1=000000&IS2=1&lt1=_blank&lc1=0000ff&bc1=000000&bg1=ffffff&f=ifr&#8221; style=”width:120px;height:240px;” scrolling=”no” marginwidth=”0″ marginheight=”0″ frameborder=”0″></iframe>

Plain text works fine, but as soon as I insert this iframe, the entire sidebar just dissappears. It doesn’t move down or anything, it’s just gone.

Any suggestions?