Crash in UIKit UINavigationItem

I have a problem with my iPhone app, I have a crash log from a tester that i ran through symbolicatecrash but I'm still not sure what could be causing it. The crash only happens on one tester's device and I am unable to reproduce it on my device.

Hardware Model:      iPhone2,1

OS Version:      iPhone OS 4.0.1 (8A306)


Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x534f5031
Crashed Thread:  0

Thread 0 Crashed:
0   libobjc.A.dylib                0x0000286c objc_msgSend + 16
1   UIKit                          0x000765c6 -[UINavigationItem _updateViewsForBarSizeChangeIfNecessary] + 30
2   UIKit                          0x000a26c8 -[UINavigationBar _popNavigationItemWithTransition:] + 212
3   UIKit                          0x000a25d0 -[UINavigationBar popNavigationItemAnimated:] + 76
4   UIKit                          0x000a2492 -[UINavigationBar _handleMouseUpAtPoint:] + 390
5   UIKit                          0x000a22f2 -[UINavigationBar touchesEnded:withEvent:] + 54
6   UIKit                          0x000614e6 -[UIWindow _sendTouchesForEvent:] + 362
7   UIKit                          0x00060e60 -[UIWindow sendEvent:] + 256
8   UIKit                          0x0005cb54 -[UIApplication sendEvent:] + 292
9   UIKit                          0x0005c500 _UIApplicationHandleEvent + 5016
10  GraphicsServices               0x00004140 PurpleEventCallback + 660
11  CoreFoundation                 0x00071aa4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 20
12  CoreFoundation                 0x00073848 __CFRunLoopDoSource1 + 160
13  CoreFoundation                 0x00074626 __CFRunLoopRun + 514
14  CoreFoundation                 0x0001d8e4 CFRunLoopRunSpecific + 224
15  CoreFoundation                 0x0001d7ec CFRunLoopRunInMode + 52
16  GraphicsServices               0x000036e8 GSEventRunModal + 108
17  GraphicsServices               0x00003794 GSEventRun + 56
18  UIKit                          0x000062a0 -[UIApplication _run] + 396
19  UIKit                          0x00004e10 UIApplicationMain + 664
20  app                            0x0000240c main (main.m:14)
21  app                            0x000023a8 start + 44

The crash happens from taking a photo, going to new view, manipulating photo, saving it, sending it, returning to the previous view and then trying to go back to the view before that.

Make sure you're properly retaining and releasing your nib objects as outlined here.