im on the kazakhstan level and im on the bit where u go on the bike.onece ive finished killing every 1 around the bike i walk up 2 it and the game stops and loads my last checkpoint.does any 1 now how 2 beat this annoying bug?

It's not a bug! Just jump down to the area where the bike is and try to defend yourself while you're waiting for the gates to open. Then just jump on, you don't need to kill everybody and you also need to keep this in mind when doing the Time Trial thing *hint hint*.