Intermittently, and silently, the dynamic headaer will not show up. The XMLSub <Apps:header /> is being processed by Apache::ASP, because it is excluded from the source of the generated page. However, it is not replaced by the header html. This problem is intermittent, and varies in frequency from ~50% to ~10%, when it is present at all.
From Paul Lindner: Usually it means that the XML/RDF didn't parse correctly. Restarting the server seems to fix it.. I'd create a special script that dumps the cached contents of the XML::Simple transformation of the RDF, I bet it comes up empty.. Will investigate. Will also look at updating XML::Simple, if possible.
I believe this problem is fixed. Diagnosis involved checking the return from the eval wrapping the XML::Simple rdf parse. It turned out there was an old rdf lying around on LIVE tag that didn't parse, but which had been deleted from QA and HEAD.