When you are trying to view a QuickTime movies from a streaming server, sometimes you will get back a 400 Bad Request error. At my network at work, we intercept all port 80 traffic and forward to our squid proxy server, which is why we get this error. In order to fix this, just open up System Preferences, open the QuickTime pane, click the Advanced tab, and choose Custom… under the Transport Setup dropdown. Choose HTTP as your protocol, and type in 7070 where is says Other. Since making this modifications, we can view the QuickTime streams with no problems.