Require in models?

Lee
2007-01-26T19:28:32Z

I am getting the error "Missing model property.rb" whenever I insert
require statements into my model (in this case property.rb). The error
occurs when I try to access my application through the browser. As soon
as I remove the require, the error no longer occurs.

My code is as follows:

require ''validation''
require ''date''
require ''time_period''
class Property < ActiveRecord::Base
...

Thanks.