Can't find the error on my page

I just noticed that I had an error on my page (bottom left corner “!” sign in IE)
http://www.olssongerthel.se/sortiment/index.php

I have no idea what the error is, but it could be javascript. If I disable ALL script on the page (with DevToolBar) the error disappears. But the only script I use on the page is javascript (from another page displayed via an iframe). The other page is http://www.olssongerthel.se/sortiment/kedja.html and that page doesn’t have any errors!

I have no clue where to begin, but this is really bugging me…

Removing the flash file didn’t make any difference
removing the iframe didn’t make any difference
removing the css didn’t make any difference

Anyone know where to begin?