class definition missing error

In my Rails app, I am occasionally getting a class definition missing
error. I see this error in my logs, and every once in a while run into
it myself, but not in a way I can reproduce. The error looks like:

/data/web/findit/Umlaut/config/../lib/hip3/bib_searcher.rb to define
Hip3::BibSearcher

But, bib_searcher.rb DOES define Hip3::BibSearcher! And the error is
not easily reproducable, it seems to crop up in mysterious places.

Has anyone run this sort of thing? Any ideas? Thanks for any.

Jonathan

is bib_searcher.rb located at

RAILS_ROOT/lib/hip3/bib_searcher.rb
or
RAILS_ROOT/lib/bib_searcher.rb