Don't know if this has been already mentioned, but
I didn't find it in the archive...
Under Windows you can have spaces in directory names.
This throws XJC if your schema has any includes or imports
with relative HREFs; it finds your original schema but not the
ones you import/include, because it can't build a valid URL
using a base path that contains spaces.
The solution is to fire up XJC with a file URL, using the non-spaced
alternative paths that Windows automatically generates.
For example, this won't work if the invoking shell is in c:\some stuff
xjc schemas\authors.xsd
But this will work:
xjc file:///C:/SOMEST~1/Schemas/authors.xsd
David