O.k., I could be way off on this. I don't really know XML that good but doesn't the schema require a "xs:" in front, e.g.
<[COLOR=Red]xs:[/COLOR]element name="Books" type="target:booksType" />
I'm just kind of taking a guess here. As I said, I could be way off.
Also, do the other require a space before the "/>"?
<element name="ISBN" type="string" />
<element name="PUBLISHER" type="string" />