And there is one more important rule regarding jumps in Czech checkers - the opponent's pieces that you have already jumped over are removed from the board AFTER the whole move is finished (in contrast to, e.g., Turkish checkers where they are removed during the jump and thus creating new jumping opportunities). However I am not sure whether this particular rule is correctly implemented here on BrainKing right now (several weeks ago I reported the bug concerning removing jumped opponent's pieces from the board during the jump to Fencer - he asked me for a link to official rules of Czech Checkers, I provided him with the link and since then I have received no other feedback from him ...)
(according to the official rules the move I was forced to play by BrainKing was illegal - I should have finished my jump at b4 (or somewhere else at the particular diagonal) because the already jumped pawn at e7 should be removed from board after my jump will be finished and therefore prevents me from jumping over the pawn at d6 ...)!