12-20-2016, 08:30 PM
Problems with a script are usually best addressed by asking the author. But if your have no alpha channel in your layer(*) (in other words if the layer cannot be transparent) the result above (cut part replaced with some default background color) is not unexpected.
(*) The layer name is in boldface in the Layers list if these is no alpha channel.
(*) The layer name is in boldface in the Layers list if these is no alpha channel.