I've gotten these at times. Drives me batty cause I'm not sure what's
causing it either. While I suspect something is requiring an older
version of facets first then you are trying to require against the new
one. But the only way for this bug to happen then is if Gems is being
"too" smart and noticing that this particular facet doesn't exist in
the old version, but does in a new version (which is the case). So
instead of saying "LoadError: no file to load --
facet/enumerable/probability for Facets  v0.7.2" It's telling you
you're trying to use a newer version when an older one has alrady been
activated. Make sense?

This is really a bad mojo on Gems. But we won't get into that.

The question is what's cuasing the old version of facets to be active.
I wonder if I have an autorequire set for 0.7.2 in the gemspec, would
that do it? I don't think I do though. Another thought: are you running
Nitro 0.23 by chance?

T.