Hmm, tried using it, but as soon as I playtest, I get an error on line 26:
remove = map.data & 0b1111
Here's a screenshot:
EDIT: I tried another one from the same author and it worked. This is the one I used:
http://rpgmaker.net/scripts/325/I'd still like to get this one to work, since seeing the auto-shadows in the editor can be a little distracting sometimes.