There are many uses of the function (some) used in this plugin, so without more information it'll be impossible for me to fully track down the cause.
Cuase the error again and open the console (f12), click the console tab, and then paste the error message it shows in there. It should give a line number, which is a good place to start.
There's a good chance this problem is happening because you're loading the plugin into a project and then loading a savefile in that project that was created before this plugin was imported. Parts of the plugin rely on some values being stored on the actors, values which are saved to them on database load, but if your savegames database was created before this plugin was installed, those values don't exist, and attempting to read them causes a crash.
~Ramza