Team test: Failing load. Request failed: The server committed a protocol violation. Section=ResponseHeader Detail=CR must be followed by LF - visual-studio

Question

The folk in the QA department use visual studio team test (2008 IIRC) to run load tests against our web application.
The latest set of tests have failed on several pages. The error reported is
Request failed: The server committed a protocol violation. Section=ResponseHeader Detail=CR must be followed by LF
Searching for this using google yields quite a few results. it would appear that this error message is generated from the .Net framework WebRequest class (i.e. it is not a visual studio specific message). The most useful result is this one, which details my exact problem and how to suppress the error.
But of course, I want to get to the bottom of why this error occurs in the first place. Here are some more facts: -
This error never used to occur when the tests were run against an older version of the web app. The web app. host OS and web server (Win 2003 and IIS 6) are identical in both cases.
Not all the pages generate this error - only some.
The only significant change to these pages (that I can think of) is that they now use some AJAX whereas before they did not (IIRC)
In order to narrow down the problem, I created the simplest page that I could to replicate the problem. Luckily, that was not too hard. I then inspected the bytes in the header using Fiddler but I could not find an occurrence of a CR (0x0D) that was not followed by a LF (0x0A).
The raw HTTP response (as stored from Fiddler by response saving bytes - so its encoding should not have been altered during the save) is here as text if you don't believe me!
So now I am left thinking that the supposed error might be a false alarm. Does anyone else have experience of this/can help shed light?

Answer 1

This is definitely not a false alarm - I've been getting this error in my app a lot while trying to communicate with Facebook API.
I've just stumbled upon this response from Steven Cheng - http://www.velocityreviews.com/forums/t302174-why-do-i-get-the-server-committed-a-protocol-violation.html - and let me quote him:
From your description, you're using
the HttpWebRequest component to send
some http request to some external web
resource in your ASP.NET web
application. However, you're always
getting the "The server committed a
protocol violation.
Section=ResponseStatusLine" error
unless you set the following section
in the web.config file:
<system.net>
<settings>
<httpWebRequest useUnsafeHeaderParsing="true" />
</settings>
</system.net>
And you're wondering the cause of this behavior, correct?
As for this issue, I've performed some
research on this and found that the
problem is actually caused by the
critical http header
parsing/validating of the
HttpWebRequest component. According to
the Http Specification(http1.1), the
HTTP header keys shoud specifically
not include any spaces in their names.
However, some web servers do not fully
respect standards they're meant to.
Applications running on the Dotnet
framework and making heavy use of http
requests usually use the
httpWebRequest class, which
encapsulates everything a web oriented
developer could dream of. With all the
recently issues related to security,
the "httpWebRequest" class provides a
self protection mechanism preventing
it to accept HTTP answers which not
fully qualify to the specifications.
The common case is having a space in
the "content-length" header key. The
server actually returns a "content
length" key, which, assuming no spaces
are allowed, is considered as an
attack vector (HTTP response split
attack), thus, triggering a "HTTP
protocol violation error" exception.
Will try if this helps right now and post results later