Q: What's a meaning of this code. EXC_BREAKPOINT (SIGTRAP)

This is a pretty strange stack trace. It's crashing in dyld (the dynamic library loader). That suggests that it's having trouble loading a dynamic library or Framework, which means it's in the loading of system code (since you can't have a 3rdparty dynamic library on a standard iphone). Notice how in the Binary Images section, your code doesn't even seem to be loaded yet (or was the rest of the dump truncated)? Do you do any manual loading of dynamic libraries (dlopen() or the like)? Even if you were, you'd expect main() to be on the stack if your program had actually loaded....

When you say they've tried reinstalling, I assume you mean your app? Does that mean they deleted your app and then reinstalled it, or something else? The most likely cause that comes to mind is corruption of the bundle. But you'd think that deleting and reinstalling would fix that up. More aggressive would be delete, reboot, then reinstall.

My next question would be whether this is a jailbroken iPhone. I'd ask the user to reboot the iPhone if they haven't already. I'd even be tempted to ask them to do a restore of the OS, but that's always an awkward thing to ask a customer to do.