Application crashes unless run from Xcode - objective-c

Question

I have this code:
NSColor *color = [NSColor colorWithDeviceHue:hue
saturation:saturation
brightness:brightness
alpha:1.0];
NSString *scriptString = [NSString stringWithFormat:
#"try\n"
#"tell application \"Adobe Photoshop CS5\" \n"
#"set foreground color to {class:RGB color, red:%f, green:%f, blue:%f} \n"
#"end tell\n"
#"on error\n"
#"try\n"
#"tell application \"Adobe Photoshop CS4\" \n"
#"set foreground color to {class:RGB color, red:%f, green:%f, blue:%f} \n"
#"end tell\n"
#"end try\n"
#"end try",
[color redComponent] * 255,
[color greenComponent] * 255,
[color blueComponent] * 255];
NSLog(#"script string: %#", scriptString);
NSAppleScript *script = [[NSAppleScript alloc] initWithSource:scriptString];
NSDictionary *error;
[script executeAndReturnError:&error];
NSLog(#"result: %#", error);
When I run it from xcode's run feature, it works just fine. When I build it as an application and run it standalone, it quite often crashes in this part.
Any idea why this might be?
EDIT: Most of the crash log (can't fit it all in here)
Process: The Color Picker Sync [1283]
Path: /Users/USER/*/The Color Picker Sync.app/Contents/MacOS/The Color Picker Sync
Identifier: com.Loupe.The-Color-Picker-Sync
Version: 1.1 (1.1)
Code Type: X86-64 (Native)
Parent Process: launchd [160]
Date/Time: 2012-01-21 14:04:54.025 +0000
OS Version: Mac OS X 10.7.2 (11C74)
Report Version: 9
Sleep/Wake UUID: 6BFBE167-51ED-433B-BB70-17D6C4054817
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: 0x000000000000000d, 0x0000000000000000
VM Regions Near 0:
-->
__TEXT 0000000101782000-000000010178c000 [ 40K] r-x/rwx SM=COW /Users/USER/*/The Color Picker Sync.app/Contents/MacOS/The Color Picker Sync
Application Specific Information:
objc_msgSend() selector name: respondsToSelector:
objc[1283]: garbage collection is OFF
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libobjc.A.dylib 0x00007fff90d8114d objc_msgSend_vtable5 + 13
1 com.apple.Foundation 0x00007fff8c239456 _NSDescriptionWithLocaleFunc + 50
2 com.apple.CoreFoundation 0x00007fff911284d5 __CFStringAppendFormatCore + 11365
3 com.apple.CoreFoundation 0x00007fff9117acdb _CFStringCreateWithFormatAndArgumentsAux + 107
4 com.apple.CoreFoundation 0x00007fff911f3182 _CFLogvEx + 114
5 com.apple.Foundation 0x00007fff8c2b3b53 NSLogv + 89
6 com.apple.Foundation 0x00007fff8c2b3af1 NSLog + 130
7 com.Loupe.The-Color-Picker-Sync 0x0000000101784103 -[StatusMenuItemSampleAppDelegate didReceiveMessage:] + 1023 (StatusMenuItemSampleAppDelegate.m:294)
8 com.Loupe.The-Color-Picker-Sync 0x00000001017848fb -[LocalRoom receivedNetworkPacket:viaConnection:] + 104 (LocalRoom.m:161)
9 com.Loupe.The-Color-Picker-Sync 0x0000000101785aa2 -[NetworkConnection readFromStreamIntoIncomingBuffer] + 416 (NetworkConnection.m:359)
10 com.apple.CoreFoundation 0x00007fff91183b7b _signalEventSync + 107
11 com.apple.CoreFoundation 0x00007fff91183b02 _cfstream_solo_signalEventSync + 98
12 com.apple.CoreFoundation 0x00007fff91183928 _CFStreamSignalEvent + 632
13 com.apple.CFNetwork 0x00007fff87459613 SocketStream::dispatchSignalFromSocketCallbackUnlocked(SocketStreamSignalHolder*) + 45
14 com.apple.CFNetwork 0x00007fff87458c72 SocketStream::socketCallback(__CFSocket*, unsigned long, __CFData const*, void const*) + 232
15 com.apple.CFNetwork 0x00007fff87458b72 SocketStream::_SocketCallBack_stream(__CFSocket*, unsigned long, __CFData const*, void const*, void*) + 100
16 com.apple.CoreFoundation 0x00007fff9117b714 __CFSocketPerformV0 + 980
17 com.apple.CoreFoundation 0x00007fff91133b51 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
18 com.apple.CoreFoundation 0x00007fff911333bd __CFRunLoopDoSources0 + 253
19 com.apple.CoreFoundation 0x00007fff9115a1a9 __CFRunLoopRun + 905
20 com.apple.CoreFoundation 0x00007fff91159ae6 CFRunLoopRunSpecific + 230
21 com.apple.HIToolbox 0x00007fff8e14d3d3 RunCurrentEventLoopInMode + 277
22 com.apple.HIToolbox 0x00007fff8e15463d ReceiveNextEventCommon + 355
23 com.apple.HIToolbox 0x00007fff8e1544ca BlockUntilNextEventMatchingListInMode + 62
24 com.apple.AppKit 0x00007fff8c5533f1 _DPSNextEvent + 659
25 com.apple.AppKit 0x00007fff8c552cf5 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 135
26 com.apple.AppKit 0x00007fff8c54f62d -[NSApplication run] + 470
27 com.apple.AppKit 0x00007fff8c7ce80c NSApplicationMain + 867
28 com.Loupe.The-Color-Picker-Sync 0x000000010178302c 0x101782000 + 4140
Thread 1:: Dispatch queue: com.apple.libdispatch-manager
0 libsystem_kernel.dylib 0x00007fff8b3cc7e6 kevent + 10
1 libdispatch.dylib 0x00007fff8bf615be _dispatch_mgr_invoke + 923
2 libdispatch.dylib 0x00007fff8bf6014e _dispatch_mgr_thread + 54
Thread 2:: com.apple.CFSocket.private
0 libsystem_kernel.dylib 0x00007fff8b3cbdf2 __select + 10
1 com.apple.CoreFoundation 0x00007fff911a2f9b __CFSocketManager + 1355
2 libsystem_c.dylib 0x00007fff90aad8bf _pthread_start + 335
3 libsystem_c.dylib 0x00007fff90ab0b75 thread_start + 13
Thread 3:
0 libsystem_kernel.dylib 0x00007fff8b3cc192 __workq_kernreturn + 10
1 libsystem_c.dylib 0x00007fff90aaf594 _pthread_wqthread + 758
2 libsystem_c.dylib 0x00007fff90ab0b85 start_wqthread + 13
Thread 4:
0 libsystem_kernel.dylib 0x00007fff8b3cc192 __workq_kernreturn + 10
1 libsystem_c.dylib 0x00007fff90aaf594 _pthread_wqthread + 758
2 libsystem_c.dylib 0x00007fff90ab0b85 start_wqthread + 13
Thread 0 crashed with X86 Thread State (64-bit):
rax: 0x0000000000000000 rbx: 0x0000000000000000 rcx: 0x00007fff6137ec80 rdx: 0x00007fff8c481ccc
rdi: 0x20200a3b31203d20 rsi: 0x00007fff76a0f730 rbp: 0x00007fff6137e970 rsp: 0x00007fff6137e958
r8: 0x000000000000000a r9: 0x000000000000057e r10: 0x0000000000000000 r11: 0x00007fca58557e21
r12: 0x00007fff91128644 r13: 0x000000000000000a r14: 0x20200a3b31203d20 r15: 0x0000000000000000
rip: 0x00007fff90d8114d rfl: 0x0000000000010246 cr2: 0x000000006a86fdc0
Logical CPU: 1
External Modification Summary:
Calls made by other processes targeting this process:
task_for_pid: 11
thread_create: 0
thread_set_state: 0
Calls made by this process:
task_for_pid: 0
thread_create: 0
thread_set_state: 0
Calls made by all processes on this machine:
task_for_pid: 4860
thread_create: 1
thread_set_state: 0
VM Region Summary:
ReadOnly portion of Libraries: Total=211.3M resident=105.4M(50%) swapped_out_or_unallocated=105.9M(50%)
Writable regions: Total=48.2M written=3504K(7%) resident=19.3M(40%) swapped_out=1856K(4%) unallocated=29.0M(60%)
REGION TYPE VIRTUAL
=========== =======
CG backing stores 8K
CG raster data 64K
CG shared images 168K
CoreGraphics 16K
CoreServices 2004K
MALLOC 22.0M
MALLOC guard page 32K
Memory tag=240 4K
Memory tag=242 12K
Memory tag=243 16K
Memory tag=249 156K
STACK GUARD 56.0M
Stack 9820K
VM_ALLOCATE 16.1M
__CI_BITMAP 80K
__DATA 21.8M
__IMAGE 1256K
__LINKEDIT 47.6M
__RC_CAMERAS 236K
__TEXT 163.7M
__UNICODE 544K
mapped file 17.1M
shared memory 312K
=========== =======
TOTAL 358.7M

Answer 1

The most common mistake: NSAppleScript can only be used in the main app thread because it shares a AppleScript ComponentInstance. But if you show up crash log it helps.

Answer 2

You need to set error to nil initially:
NSDictionary *error = nil;
[script executeAndReturnError:&error] will change the value of error only if it fails. That's why you get a bad access if there's no error.