migration error

Hi, when I try to migrate this:

class AddPrice < ActiveRecord::Migration
  def self.up
    add_column :products, :price, :decimal, :precision => 8, :scale =>
2, :default => 0

  def self.down
    remove_column :products, :price

I get this error:

rake db:migrate

in C:/rails/depot
== AddPrice: migrating ================================
-- add_column(:products, :price, :decimal, {:default=>0, :precision=>8,
rake aborted!
You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occured while evaluating nil.[]

The one thing I've noticed that is kind of strange is that :default=>0
has moved from beeing after precision and scale to be before it.

I've installed edge (I think at least, is there a way so check that?)

Thanks in advance