Hi Katya,
I am trying to reproduce the first error (TypeError 'undefined') and now I am having troubles being able to do so. I guess that is a good sign, but I am going to continue trying to reproduce it.
As for the warning (Plugin should use a background thread) this occurs when I run the app, and cause any type of notification to pop up. Like when you enter an incorrect username and password.
I am using xCode 5.1.1 and running it in OSX Mavericks.
Is this warning anything to worry about, that I should address?
Thanks