probability and EV question

Hello all,

I am a new poster here so please bear with me if I ask dumb questions.

In the current issue of "Top pair" magizine there is a artical showing the win rates of verious hands by the number of players if no one folded. If I am reading tis correctly. Ten players see the flop you hold AA, No one folds. You should win 31.06% of the time. Nine players 34.70% and so on. So If every time I get AA and call to the river I can expect to have a positive EV. Now if I've got it so far and I take it to the opposite extreme I play 64s ten handed I should win 11.15, again a positive EV.

I have been using "Poker tracker" since playing online and have no got into a pot with anything near as bad as 64s with out being in th big blind, but still I have seen my bankroll drop at a alarming rate. I also play in the casino's and do good, not great but good.

Help?!?!?!?!