Your rock texture is way too big and your sky texture is way too small. You're going to have to learn how to apply and use UVW modifiers in order to get your textures to behave. I'm not sure if I have already posted this link for you, but this tutorial explains the basics of UVW mapping pretty well: http://waylon-art.com/uvw_tutorial/uvwtut_01.html
How did the book tell you to do the sky? Is it a texture applied to a flat plane or is it a background environment map? Either way, you're going to have to learn about UVW mapping and make adjustments to the size and tiling of your textures in the material editor and in the UVW mapping parameters.