Help with crash log EXC_CRASH (SIGABRT)

Can anyone assist with how to interpret this crash log? A user from Switzerland emailed this log from his iPad. I have been able to symbolicate the report but do not know how to interpret the cause of the problem. The app crashes instantly upon launch for him. I cannot duplicate this error and am new to debugging. Thanks.

Please see the attachment for details

Help with crash log EXC_CRASH (SIGABRT)
 
 
Q