After port app WP7 to WP8 throws exception “The thread has exited…”"

Question

After port app WP7 to WP8 throws exceptions in output:

The thread 0xaac has exited with code 259 (0x103).
The thread 0xabc has exited with code 259 (0x103).
The thread 0xad8 has exited with code 259 (0x103).
The thread 0xb04 has exited with code 259 (0x103).
The thread 0xb0c has exited with code 259 (0x103).

But in emulator all works great.
Why these exceptions occur?
Will this work on real device?

Note: I use WebClient .

Answer 1

That doesn't look like an exception, but a thread exit code (I'd guess probably due to a ThreadPool thread being ended). I see these extra lines in the Debug window and my app is working fine.