Ah, OK. I thought you might be using the side-battle script for XP and hence needed the correct battlers.

I forgot to make the diagram, too. Sorry.

Basically, the grass needs to be right at the bottom (if you don't know, then it's the level where the icon is the orange plane below two grey planes), and the house and whatever else needs to be above (either orange plane in the middle, or on top).

If that doesn't solve the problem, then you may need to play around with the chipset and change the colour to be transparent, etc.