Download System Files, Here Link
Replace to your "Gravity Folder"
edit itemInfo.lua again and Save As to itemInfo.lub
or
you can use this tool [Lua To Lub Converter]
Here Link
How To Use ?
1. Copy "Cmd.exe" to your tool file[Lua To Lub Converter] [Don't know what is "Cmd.exe" ?(E.g: Picture Below)]
2. Copy "itemInfo.lua" to your "Tool Folder"
3. open "Cmd.exe" and type "luac5.1.4.exe -o itemInfo.lub itemInfo.lua" And Hit "Enter"
Like Picture Below:
4. Done [Copy "itemInfo.lua" and "itemInfo.lub" from "Tool Folder" to your "Gravity Folder]