The code listed in Chapter 12 has many errors, such as typos and wrong project, namespace, type and member names (one name appears in the listing, a different one in the body text).

Besides, I can't get PaymentAccepted to work—and, consequently, nothing beyond this point.

I tried the downloaded code, to see how things should work, but it throws exceptions, which I don't know how to handle...

I'm very disappointed at the low quality of this book. The experience is quite frustrating. I want to learn, but this book won't allow me.