Or user error, but it doesn't sound like an OS problem. If the game is played with a web browser it is most likely a problem with the functionality of the website itself.
I belong to an online bingo league and one of the Tournament Directors in training is having a problem when she goes to click on the name of the winner of a game, instead of it posting the win, an email screen for that player comes up. The league is set up in its standings list to do that, but it shouldnt be doing it in tournaments. I have asked the league, Cases Ladder, how to solve the problem but they have no answer. She is running Vista, but I dont know much else about her computer. She has asked the computer manufacturer with no results. I just found out that her daughter has a computer in the same house with XP and when this lady tried, it did the same thing on the second computer also. Anyone know why it might do something like this on two computer with different operating systems in the same home? And especially how to make it stop this?