however it seems strange to me, if it worked well in the first part it should work fine till the end so if I understand correctly you are talking about where you need to jump the first time, I think you just forgot to run before you jump .. if not run the jump will be too short and you cannot continue,
if I guessed it means that I have to make the message that says to run more visible, the checkpoint is right there if you do continue instead of a new game you should start from there, let me know :)