First of all, ask your question here:
https://groups.google.com/forum/#!forum/mitappinventortestThat is the support forum. This is the developers forum.
Second: Did you check what your PHP really returns? It may be different from what you think.
For example, put in a notifier yo show what the responseContent and responseCode is, or try the url you are sending in a browser, which allows you to see more easily what is going on.
Cheers, Ghica