I'm getting the following error after a crash in an iPad app that uses CoreMIDI (The * are to blank out the app name):

Dyld Error Message:
 Symbol not found: _MIDINetworkNotificationContactsDidChange
 Referenced from:
/var/mobile/Applications/8F08B78E-929D-4C5A-9F02-08FD5743C17F/***.app/***
 Expected in: /System/Library/Frameworks/CoreMIDI.framework/CoreMIDI
in /var/mobile/Applications/8F08B78E-929D-4C5A-9F02-08FD5743C17F/***.app/***
 Dyld Version: 179.4

When the app launches, I listen for MIDI Network Sessions using

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sessionDidChange:) name:MIDINetworkNotificationSessionDidChange object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sessionDidChange:) name:MIDINetworkNotificationContactsDidChange object:nil];

Which seems to be what is causing the crash. This is after I call

session = [MIDINetworkSession defaultSession];
session.enabled = YES;
session.connectionPolicy = MIDINetworkConnectionPolicy_Anyone;
MIDIClientCreate(CFSTR("MidiManager"), midiNotifyProc, (void*)self, &midiClientRef);

This kind of looks like CoreMIDI library has not been included in the build. Problem is, it IS included in the build as a required framework. (And the deployment target is set to 4.2). I can run the build fine on my iPad and have been testing extensively with other users' iPads also with no problems whatsoever. Also, this is an update to an existing app that has had several updates already with no problems.

I just double checked my deployment build and the framework is definitely included, and I just installed that build onto my iPad (with a different provisioning profile from the store) and it works fine also.

What could be happening? Could it be that Xcode just did a bad build for the one I sent to Apple, or am I missing something obvious? Could I change the MIDINetworkNotificationSessionDidChange notification symbol to a literal string (@"MIDINetworkNotificationSessionDidChange") to fix things for the mean time?

Thanks for any help!