uninitialized constant

Hi,
added following line after listening to one of the railscasts on
formatting date and time:
Time::DATE_FORMATS[:due_time] = "%I:%M %p"

Now i am adding a new column to one of my tables in the database and
rails is giving following error:
/var/www/html/myapp/pms080204/config/environment.rb:59: uninitialized
constant Time::DATE_FORMATS (NameError)

Please help.
Thanks.