What is the best strategy to beating all the levels in stack cannons in Starcraft. I can get to the second boss, which is 3 ghosts with about 3000 HP each. They just walk right through my base or destroy some walls. I think there are many variations of this game in starcraft, but I play one called "Stack Cannons on your own".

EDIT: Here is a download link if you wanted to try it. Put it in the following directory C:/program files/starcraft/maps/download