Well, for starters there's a message there telling you to update the YEP_CoreEngine plugin.
I'm guessing your version of MV, your project version, and/or your plugin versions are not compatible.
And did you add a plugin and then try to resume a game that you'd saved prior to adding the plugin? If that happens, start a new game and see if the error still occurs.
But you really need to make sure MV, your project, and your plugins, are all up to date.