I've seen a lot of posts regarding problems with piping but I haven't seen anyone mention the problem I was experiencing. Apparentley the are a number of things that could go wrong with piping but here is the problem I was having.
I was receiving a return message saying that there was a permanent error.
PHP Parse error: syntax error, unexpected T_VARIABLE in /api/pipe.php on line 88
I checked the code and found there was a missing semi-colon. I changed
this $var=$parser->getHeader()
into this $var=$parser->getHeader();
and my problems were solved.
I'm not saying this is the problem you are having but that was my problem