I want to know why I cannot succeed at online poker. I am a successful real-life player, but why can't I make money online?

I once had a nice couple weeks and won about $1000, but soon went down to 100, back up to 500, back down to 50 and now I am at 200. I don't want go through anymore swings like that! I just want to steadily increase my bankroll.

I play limit and no limit holdem. Limits at .50/1 and NL .25/.50. I am disciplined but I always seem to get beat. I play on pokerstars and like the site, but sometimes I get into cold decks and wont see a hand for an hour. When I play I like to play about 3 or 4 tables at a time, is this a problem?

I post and view these forums everyday, so I am hoping someone can help me. Thanks for reading.

Murs