Hi, I ran the schema at: http://www.psc.edu/~lfm/Grid/UR-WG/urwg-schema.11.xsd through the official W3C validator at: http://www.w3.org/2001/03/webdata/xsv and got the following errors: http://www.psc.edu/~lfm/Grid/UR-WG/urwg-schema.11.xsd:327:3: Invalid: attempt to derive a complex basetype from a simple base: ConsumableResourceType http://www.psc.edu/~lfm/Grid/UR-WG/urwg-schema.11.xsd:336:3: Invalid: attempt to derive a complex basetype from a simple base: ConsumableResourceType What tools have you used to validate this schema? And do you have any comments on the errors above? Thanks, Thomas