The server committed a protocol violation.

Hello,
I have an application that remotely connects to another XML based API. 
Today I received the error:  

The server committed a protocol violation. Section=ResponseStatusLine

I am assuming that the headers received from the 3rd party is somehow invalid for IIS to process.  I am using this app on ASP.NET 2.0.  I have tried the suggestion of setting the following in the web.config to no success:
<system.net>
        <settings>
            <httpWebRequest useUnsafeHeaderParsing="true" />
        </settings>
    </system.net>
The application runs, but I still get the same error message.


Below is the line of code that causes the issue:
      &nbs ...