Recently we had to troubleshoot an Internet Explorer problem with a force download ASPX script. The download script was being called from a Flash movie. After the call to the download script, all outgoing Javascript calls from Flash were either loading in the Address Bar and not being executed as Javascript (IE6) or were throwing errors (IE7).

It was a black box situation where we only had HTTP access to the server. We needed to examine the HTTP headers to determine if they were a contributing factor to the issue. But how? We found this clever Firefox Add-on that did the trick: HttpFox