Is the capture of my opponent allowed? Before i have played, i read the rules and this isn't related, so not must be possible, i guess.
Seeing the rules, that type of situation will only be possible in russian checkers: "If pawn jumps to last row, it promotes and continues jumping immediately".
Mysterio619: The rules do not say anything specific about this situation, so the rules of Czech Checkers will apply analogously. Since the rules of Czech Checkers do not allow an umpromoted piece to continue jumping after promotion, the situation in your game has to be considered a bug.