My minecraft says running out of memory?

I enjoy playing minecraft but lately every time i put down a block it says Warning: Running out of memory! So they cover up all over my screen and I can't see. I don't want to lose all my good maps

Added (1). On ipad

Guest

Same here, on iPad too! I just updated and when I made a new world, it said that after a couple of minutes. My main map is undisturbed, but I want to take full advantage of the PE update!

Angie