Issue with creating log in production mode using Rails Logger

I hosted my Rails 3.2.13 application in (Ubuntu 14.04 + Passenger + apache2) combination server.

Everything is working perfect in development environment; but in production environment. I got error like below :-

In browser

We're sorry, but something went wrong.
We've been notified about this issue and we'll take a look at it shortly.

Than, I decided to take log report in log/production.log and done some changes like below.

In /config/environments/production.rb file:

config.consider_all_requests_local = true
config.log_level = :debug
Rails.logger = Logger.new(STDOUT)
Rails.logger = Log4r::Logger.new("Application Log")

Even than, log report is not created in /log/production.log file

Do I need to do anything else ? kindly someone assist me to resolve this issue.