Dynamic Finders Return nil

Hi,

Shop.find(123) - returns the shop
Shop.where(:id => 123) - returns the shop
but
Shop.find_by_id(123) returns nil
same for find_by_name, etc.

Here on Mac OS X with PostgreSQL, Shop.find_by_id and find_by_name
return the expected instance.

Could it be linked to sqlite3 or Windows?

-- Thibaut