using <oXygen/> to make *.html files from pearweb

I'm trying to use <oXygen/> to make *.html files from pearweb and am having
some difficulty doing so.  I tried to open an arbitrary *.xml file and
convert it to *.html using the Docbook HTML Transformation Scenario and got
a bunch of "entity not defined" errors.  What do I need to do to get these
entities defined?

I'd prefer to convert every *.xml file, en masse, with <oXygen/>, but given
that I can't do one file, doing all of them doesn't seem all that feasible.