My Provisioning Profile for my iPhone app expired, so I renewed it, downloaded it.  Added it into Xcode.  Manually added it to ~/Library/Mobile Devices.  It would build and install onto the device, but when launched via the debugger I received the following output:

Error launching remote program: security policy error.

The app would terminate, the debugger was running but not attached to any process.  The fix that finally resolved it was going to Settings > General > Profiles on the device and removing all of the expired Profiles in there.  (Which were not related to the app in question.)