Recently we transfered a web-application (PHP 4.4.9) from a Linux/Apache to a Win2003/IIS6 webserver. Now we've noticed a problem with pages containing a Header(Location:...) statement, instead of being redirected to the specified link, some users get "Page cannot be displayed error". The links in the Header statement aren't fully qualified urls most of the time. We've only noticed the problem with IE browsers. Some users (with IE) don't have the problem at all.
I've asked a colleague of mine, to give me some information using the tool Charles, but when the tool is active, the problem disappears, only the return when Charles is turned off. I noticed at difference between IE and Firefox, using Charles. The response header of such a page, contains "HTTP/1.1 302 Moved Temporarily" when using IE and "HTTP/1.1 302 Found" when using Firefox.
I'm hoping this behavior sounds familiar to someone, since the problem is really blocking a lot of our customers.