Redmine

this is a bitnami installation- i am trying to upgrade from version 1.2.1 to 1.3 and when i try to update the database with the following command:

"rake db:migrate RAILS_ENV=production"

i am getting the following error:"

"(in /opt/redmine-1.2.1-2/apps/redmine)
Please install RDoc 2.4.2+ to generate documentation.
rake aborted!
Can't connect to local MySQL server through socket '/opt/redmine-1.2.1-2/mysql/tmp/mysql.sock' (2)
(See full trace by running task with --trace)"

how can i fix that issue in order to finish upgrading the redmine?