I believe this is a bug in IE6 actually, and is fixed in IE7, update! We have to use an iframe (i think) to take news from a 3rd party blog (wordpress) and display this on an HTML page.
(that meaning a page with file extension .htm or .html).
We could use other methods, but would have to change all page names to end in something like ".php". This would make all links to us broken, anything on any other site would no longer work... Bad idea.
But we haven't found any solution yet for IE6 to properly use the iframe that targets a dynamically created "parent" frame.
If you know the answer let us know! :0