I had the impression that the problem was the pass to TD, which went slightly forward, not his knock on, which was fine since it came off his boot. So they were actually called for a forward pass, not a knock on IMHO. TBH i didn't hear what the ref or commentators said as I was watching it down at the pub, so it might be that Joubert gave a different explanation.
Hmm personally never got annoyed by Jonathan Davies, always thought he did an alright job in the games I've heard him commentate. I got really annoyed at the commentator in this game though. Thought he was really biased towards Wales (not only cheering for them, but always criticizing the ref for just about every decision against Wales and saying how he was too lenient on the Aussies, like when he didnt card Palu for his beauty of a tackle). It also annoyed me when he was whinging about Sharpe taking the conversion.