The Log tab and/or the log directory in your user directory or Alt.Binz directory, depending on your setup.
You'll need to clarify your problem, as the OP refers to both decoding and unraring, which aren't the same thing. If it's unraring that's the problem, restart Alt.Binz to see if it shifts, otherwise read through this and the many other threads about par2 & unrar. yEnc decoding of articles is another issue.