Overall, I like this audiobook, but if you're using it to help your child learn German, you really do need the illustrated book. Without the pictures, most kids are going to have a difficult time following the story.
By age 10, kids are going to find the narration extremely condescending (for example, "You're about to start a wonderful adventure!" in a saccharine voice). It's better for 4-6 year olds, and even then, you may want to fast forward through the intro after the first time or two.