awsome! but need help please!!!

That was a great tutorial and thank god for the download link that helped me alot, but the problem is that when i make new walls i can only make up to the instance name wall6 ? when i try make a wall7 and u test the game i drive straight through wall7 but everything else is fine i also tryed numbers above 7 but none of them work either!!! please help im in desperate need to finish my game!! thanks