FOSS gamedev and creative worlds

ok i like a challange so i downloaded a Mod Mobs from PilzAdam(which is a great mod)
but it goes to an error

LuaError:error function on step enter a index number

help pls

The simple mobs mod does not work with 0.4.3 stable. Try the latest dev version (Linux: compile it yourself, Windows: sfan5's windows builds)