I'm confused on whether you are trying to load the save game or just start a completely new game as Japan. If it's the former then I'd recommend giving up on it, since it sounds like you only played a turn or two. My guess is something was changed between the save and the current state of the mod you have.
If it's not letting you play as Japan at all though, then that's tougher. I'd say delete the mod entirely and download the new version I'll be posting in the near future. If you do a complete wipe then the fresh version should solve that issue.
oops over the christmas break i had forgotten to reply. i eventually managed to start a game with japan after many attempts and now it always starts fine.oh just seen there's a new version so thats awesome and i'll try that too