I have the same problem, but with mods! It says there's no manifest, yet there is. Oh, and i can actually import worlds into minecraft ed.
Yes, actually! Basic sites are tynker, and other things, where you change the color of pixels. But there are sites and programs that can add Images. Though they may only be for java.
This happens for me a lot too, even while hosting. In a world, staring it up. joining. No matter what, if i press a host button, it has this message.