Troubleshooting recognition failures?

How does one go about troubleshooting a “Routing Error” “Recognition

I’ve used the Webrick log to get down to a “recognize_path(path)” call
in /actionpack-1.12.1/lib/action_controller/routing.rb and put a
logger.debug path there, but that just told me what I already knew, and
the definition of “recognize_path” looks like its dynamically generated

PS: Interestingly, I only get a traceback to routing.rb running as root.

PPS: My apologies if this query shows up multiple times. For some
reason my attempts to send via the mailing list seem to be failing.