Fedena installation: Error

am getting error:

rake db:migrate
(in /home/hsrai/public_html/ERP/ERP_Campus/projectfedena_v2.0)
rake aborted!
can’t activate , already activated prawn-0.11.1

Where is problem?

Fedena is Ruby on Rails (RoR) application.

My installation log is below signature.

mkdir ERP
cd ERP
wget http://202.164.53.122/ERP/ERP_Campus.tar.gz
tar -zxvf ERP_Campus.tar.gz
cd ERP_Campus/projectfedena_v2.0/
sudo apt-get install rake ruby1.8-dev
rake gems:install
sudo gem install rails -v=2.3.5 --remote
sudo rake gems:install
sudo gems install prawn
joe config/database.yml
sudo gem install mysql --remote
rake db:create
rake db:migrate
ruby script/server