Re: An internal server error was encountered while attempting to transmit the message

You code is not throwing the exception, it is wrapped in a try/catch block.
However your component does read thru the incoming stream and leave the stream position at the end of the message. So when the next component or end point manager receives the message it is effectively empty.
You need to rewind the stream back to the beginning  – stream.Seek(0, SeekOrigin.Begin); before you return from your Execute method.