As a fellow Aussie i can say that we do not pay income tax on gambling wins. The only reason he might have got in trouble was that he announced on the broadcast and in newspaper that he played professional. In that case it was thought that he would have to pay taxes, but obivously he did not. This is a huge win for all Aussie poker players and makes me very happy.
Basically this ruling means that you should be able to gamble professionally and never pay taxes in Australia.
It should be noted however that he got 30% of his winnings witheld in the US and i am unsure if he ever managed to claim that back. (If he had an EU passport he could have claimed that back).