Rails - Sep 2005 - ActiveRecord find_by_field doesn't work in Production?

I had some queries like so:

@results = SomeTable.find_by_name

That works find in Development. I deploy the site, and no worky. I change it to
SomeTable.find_all_by_name and it starts to work.

What''s right/preferred? Is this simply a bug or have I perhaps done
something
wrong somewhere?