Thanks Eric for your response. It looks like the issue repro's from some machines and does not repro on others. I haven't been able to find the difference yet but thought I will post the status to see if you have any debugging ideas.
This is an external url so I don't have visibility into the server logs. However, on the client side, I don't see any changes to User-Agent, etc. Below is the request and response.
GET http://www.media-server.com/m/p/fbqsmu6b HTTP/1.1
Accept: text/html, application/xhtml+xml, */*
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko
Accept-Encoding: gzip, deflate
HTTP/1.1 504 Fiddler - Receive Failure
Date: Tue, 28 Apr 2015 20:54:01 GMT
Content-Type: text/html; charset=UTF-8
Cache-Control: no-cache, must-revalidate
[Fiddler] ReadResponse() failed: The server did not return a complete response for this request. Server returned 0 bytes.