Redmine

I tried to configure it to use my google account.
But I got the error:
An error occurred while sending mail (can't convert Fixnum into String)
I'm using redmine revision 2453

Below is what I did the configuration:
1. download smtp_tls.rb and put it into lib folder
2. add require 'smtp_tls' in production.rb file
3. edit email.yml

1. Outgoing email settings

production:
delivery_method: :smtp
smtp_settings:
address: smtp.gmail.com
port: 587
domain: gmail.com
authentication: :login
user_name: XXXXX@gmail.com
password: 123456
My password is pure numbers, is it caused this error?
Anyone can help me out this trouble?