Xcode 4.5 problems - breakpoints I don't want and libc++abi.dylib uncaught exception

I'm trying to run an app using iOS6 SDK. I'm having two problems

1) there are breakpoints in the app that I don't want - though I can deactivate those.

2) There appears to be an uncaught exception in the code. I'm getting an error message that says, "libc++abi.dylib: terminate called throwing an exception."

I was able to build the app successfully before. FYI, the only change I intentionally made was to the applicationDidLoadWithOptions event. I added some UIAppearance API code to customize the app's navigation bar.

Will someone please tell me how to fix the problem?

 

Update: I found the offending code after looking at the output. The output said the exception was caused by an innocent piece of code. Here's the offending code:

Code:

[[UINavigationBar appearance] setOpaque:FALSE];

I added the code because I want my background image to be opaque. I removed it, and the app now runs successfully.