Anyone have an idea why this regex wont validate email addresses?

Just purchased the book RailsSpace (Rough Cut Version) and I am going
through the tutorial for the user model. It says to add the code below
for email validation to your user model, which I did.

It then tells you to create a username email and password in IRB to
test it which i did. But each time it says the email is not a valid
email even though i have tried 5 or 6 different emails etc.

Went through the code with a fine toothed comb, tried a couple other
regex's i found on google, but to no avail.

Anyone take a look at this for me, and see if they spot anything
amiss?

Thanx,

Dave

class User < ActiveRecord::Base

  # Max & min lengths for all fields
  SCREEN_NAME_MIN_LENGTH = 4
  SCREEN_NAME_MAX_LENGTH = 20
  PASSWORD_MIN_LENGTH = 4
  PASSWORD_MAX_LENGTH = 40
  EMAIL_MAX_LENGTH = 50
  SCREEN_NAME_RANGE = SCREEN_NAME_MIN_LENGTH..SCREEN_NAME_MAX_LENGTH
  PASSWORD_RANGE = PASSWORD_MIN_LENGTH..PASSWORD_MAX_LENGTH

  validates_uniqueness_of :screen_name, :email
  validates_length_of :screen_name, :within => SCREEN_NAME_RANGE
  validates_length_of :password, :within => PASSWORD_RANGE
  validates_length_of :email, :maximum => EMAIL_MAX_LENGTH

  validates_format_of :screen_name,
                      :with => /^[A-Z0-9_]*$/i,
                      :message => "must contain only letters, " +
                                  "numbers, and underscores"
  validates_format_of :email,
                      :with => /^[A-Z0-9._%-]+@([A-Z0-9-]+\.)+[A-Z]
{2,4}$/i,
                      :message => "must be a valid email address"

  def validate
               errors.add(:email, "must be valid.") unless
email.include?("@")
               errors.add(:screen_name, "cannot include spaces.") if
screen_name.include?(" ")
    end
end

fixed it. Guess i needed to restart Instant_rails.