I get the same error in A7 Commercial, too.
I created a block, enlarged it, made it hollow, then textured with one of the included sky textures. I placed a camera and even two light sources, but I get the same error: E003 - no visible blocks in map. I have another map of a 2048x2048 terrain and get the same error when trying to attach the sky texture on the enclosure box--a non animating texture works fine, but any animated texture yields the same error, E003.
Anyone ???