You cannot visit a Web site if you pass the address through an ActiveX control in IE7 tha accepted extended characters as parameters
After you upgrade to Windows Internet Explorer 7, you may receive the following HTTP status message from a server:
404 File not found
You receive this status message if you pass the URL address through an ActiveX control that accepts extended characters as parameters.
This issue occurs when an ActiveX control uses the InternetOpenUrl API, an API that Microsoft Internet Extensions for Win32 (wininet.dll) exposes. When the ActiveX control passes extended characters from the URL as a parameter to the InternetOpenUrl API, extended characters are removed from the URL. The resulting URL address will be rejected from the Web server, and you will receive a "404 File not found" HTTP status message from the Web server.
The changes that were implemented in Internet Explorer 7 included a fix that addressed an international character encoding issue. This fix cannot be removed from Internet Explorer 7. Additionally, the fix to Internet Explorer 7 has insufficient context to enable Internet Explorer 7 to selectively behave as earlier versions of Internet Explorer behaved.
To work around this issue, you can use an ActiveX control that uses the InternetCanonicalizeUrl API before the URL is passed to the InternetOpenUrl API. The InternetCanonicalizeUrl will convert extended characters into the escaped versions of these characters, and the InternetOpenUrl API will not remove these escaped characters. You may want to contact the manufacturer of the ActiveX control that exhibits this behavior to obtain a version that uses this workaround.