acts_as_state_machine: make initial state exists!

Ugh.. I tried out acts_as_state_machine and I kept getting this nil error and I had no idea why. I mean, I followed the code in agilewebdevelopment.com properly. Here's the code in that website:

acts_as_state_machine :initial => :created, :column => 'status'

   # These are all of the states for the existing system.
   state :submitted
   state :processing
   state :nonprofit_reviewing
   state :accepted

Oh... apparently, you need to add

state :created

to it as well :)