I have been doing some tests with the file archetype.xsd available on the webpage and I have run with some problems. The main one is regarding BaseTypes.xsd, which supposedly defines types such as intervalOfInteger, intervalOfDate..., but doesn't contain them. Documentation (http://www.openehr.org/svn/specification/TRUNK/publishing/its/XML-schema/documentation/BaseTypes.xsd.html#h888547087) says otherwise, so I'm not sure how are documentation and schema generated/related.
I suspect that schema is out of date, but I don't quite understand how a supposedly autogenerated documentation and his XSD disagree. I know that this kind of approach is being left behind, but at least a version public on the webpage should be complete (take note that I'm not talking about being correct regarding the specifications, for the moment I just want to compile it) Another thing I have detected is a mix of CamelCase and underscores on the types definition of current BaseTypes.xsd. There are things like DATA_VALUE or DV_DATE_TIME but also archetypeNodeId, atCode, or Iso8601DateTime.
