Need help with "add backdrop" action

So in my game I'm creating random worlds each time using an engine I made. I'm also creating a minimap that basically reflects the world in a smaller 100x100 square. When the engine that's creating the world is over, I'd like to paste the small 5x5 square tiles of the minimap into the background and then destroy the actives so I can reduce the object count in my frame. However when I try to do this some weird stuff happens. It seems that the image that is pasted on screen isn't what I wanted. It's pasting the minimap from an earlier stage of my engine in which it tries to randomize the tiles.

For example, here's what I would want it to look if it was pasted in the background. This is when its not pasted:
https://dl.dropbox.com/u/4459105/Med...41.11%20PM.png


Here's what happens when I try to "add backdrop" and then "destroy" the active:
https://dl.dropbox.com/u/4459105/Med...41.28%20PM.png

I'm assuming it has to do something with my fast loops and how the screen doesn't get updated until the loops are done or something like that, not sure. Here's my .mfa file. Go to the game frame and it's line 87.
https://dl.dropbox.com/u/4459105/Med...map%20Help.mfa