Update the handling of @common-xml@ paths to permit
using an XML Catalog file to resolve these references in
the oXygen XML editor.
A sample catalog file is included, which needs to be
customized on your system to reflect the actual local
filesystem path to the common_xml directory, and then
oXygen needs to be configured to use this catalog file.
Once these steps are done, oXygen should be able to
validate the guides.
Each guide that uses this facility has been updated
accordingly.