Try not unpacking it and see if that helps, by that I mean dump the relight folder inside the zip without unpacking. Go edit the xml, save, and this is important, winrar will prompt you to overwrite the contents inside the zip, click save changes. Then fire it up and tell me what happens.
In anycase a standalone version will be releasing soon that can be toggled on in the mod menu and it will override the base game and modded maps environment file from being loaded and load the updated relight one it has.