Info targeted to frame by host app - opening in a new Window in IE7

I have a host based application which when called from one frame, returns forms and/or information into another frame. IE5 and 6 work fine. When used in IE7, the returned html stream is sent to a new window (not tab) instead of going to the target frame in the original document.

Is there a problem with IE 7 in handling these interactive streams targeting frames?

Thanks,

Steve

[423 byte] By [Egret] at [2007-12-24]
# 1
After some experimenting and research, I discovered the problem. There are several sites under the URL regis.state.va.us. Some of the pages that were pointing to the sites underneath using the URL www.regis.state.va.us. Apparently previous versions of IE and the other major browsers knew enough to throw out the www., but IE7 did does not, and therefore did not recognize the calling window as the destination and opened a new window.
Egret at 2007-8-31 > top of Msdn Tech,Internet Explorer Development,Internet Explorer Web Development...