I got a really weird problem with ZXing 2.0 on iPod touch (Version : 5.1.1). I searched on the Internet and Stackoverflow but i think i just ignore the origin of that issue so i couldn't find anything. I coded an app which successfully using ZXing running on iPhone Simulator 5.1 and when i try to run on any iPod device (i didn't test other device yet), it compiles and crash at running with no log in console (and i cant type anything on it).
This is the screen that appeared on XCode (i got the developer version 4.3.2) with a green arrow for the last line pasted and "signal SIGABRT" written.
libsystem_kernel.dylib __pthread_kill:
0x35e70324: mov r12, #328
0x35e70328: svc #128
0x35e7032c: blo 0x35e70344; __pthread_kill + 32 (arrow for this line)
I think it's related to the libZXingWidget.a static library and I configured the build settings for armv6 armv7 and i386 in two different configurations but didn't work either.
I have no idea anymore, thanks for any suggestion !
EDIT : I forgot to mention that the next thing on the thread stack is GSRegisterPurpleNamedPort.
Try rebooting the device. Coring in GSRegisterPurpleNamedPort is pretty common under certain conditions, for example switching between a debug version and an archived ipa. In that case, it's a Mach thing and seems to require a reboot. From what you've said, it doesn't sound like the issue, but it's worth ruling out.
Otherwise:
ScanTest to run on your device?