I went all in preflop, had the winning hand, but wasn't taken in account at the end of the hand.

The next hand I was still marked all in, with 0 chips, had the winning hand again, and recieved a 300 chips side pot.

Nothing special happened connection wise on my computer. Maybe it's a gpokr bug and you can look after it :) (I played a few thousands hands here a while back and never saw such behaviour)