LuaUI error

[BlasterNT]

Does anyone know how to fix this and why it occurs?
0] Loading LuaUI
[ 0] Using LUAUI_DIRNAME = LuaUI/
[ 0] Reloaded ctrlpanel with: LuaUI/ctrlpanel.txt
[ 0] Lua LoadCode pcall error = 2, luaui.lua, error = 2, LuaUI/widgets.lua, [string "LuaUI/widgets.lua"]:33: attempt to concatenate global 'MODUI_DIRNAME' (a nil value)

Thanks