Tiles are completely invisible!

I have worked on my game for a little bit now and the physics and all work perfectly fine (there are 4 gravity directions), however recently tiles are completely invisible.
This is how it looks in editor:

This is how it looks while playin:


The collisions work fine, but the tiles just don't show up.
Help? 

bump

Does this happen even after you use Run -> Clean Project?  Are you testing using Flash or something else?

If possible could you send the game through PM (or another sample if the bug is reproducible in another game)