From what version did you update? I made SOME changes to the save files over the last few updates. Your problem might originate form these changes. As stated in the latest update log, old save files will not work any more. As a small disclamor the next update will be out soon and will see some changes to the save files again. I am terribly sorry but the plugin as a whole is still under some heavy development. Could you send me your save file so i can better identify the error?