The 'problem' with gambling is the "losing". One can gamble until the cows come and it is not deemed either an addiction or a 'problem' if the individual derives a profit (or does not lose).
I would say that gambling addiction is more than losing. Like NextToYou pointed out there can be a skilled winning player who is totally addicted to playing, so he utilizes his addiction to make a profit. But the addiction can harm other parts of his life, so it becomes a problem that way.
However, people going to Gamblers Anonymous groups have usually lost heavily and this has caused problems in their life. I really don't believe there are many winning poker players there trying to get help to stop playing.
tofu23 said:Stop the losing - stop the 'problem'. Agreed that you can lead a horse to water but you can not make him bet a bonus wisely.
I would actually say that losing at the beginning might be a saving grace if it discourages potential problem gambler to continue playing right at the start. But once a problem gambler hits a large win there will be no limit
how much he will lose because he always believes that some day he can repeat that win.