I had this same problem, however in a little bit different situation. One day my application launches fine (using developer provision), then I do some minor editing to my Entitlements file, and after that it stops working. The application installed fine on my device, however every time I tried to launch it, it exited instantly (after the opening animation). (As I made edits to other files too, I did not suspect the following problem)
The problem was in the Entitlements file format, seems so that the following declarations are not the same:
Correct:
<key>get-task-allow</key>
<true/>
Incorrect:
<key>get-task-allow</key>
<true />
Altough it's an XML format, do not use spaces in the tag or the Xcode will not be able to connect to the process.
I was using developer provisioning profile all along.
Edit: Also make sure the line ending in your Entitlements file are \n (LF) instead of \r\n (CRLF). If you edit the entitlements file on Windows using CRLF line endings may cause your application to fail to launch.