Permission denied

[canedy]

I'm receiving the following error. Can someone lead me in the correct direction to resolve.

bcm2835_init: Unable to open /dev/mem: Permission denied
Thin web server (v1.6.1 codename Death Proof)
Maximum connections set to 1024
Listening on 192.168.2.31:3000, CTRL+C to stop
/home/pi/.rvm/gems/ruby-2.2.1/gems/redis-3.0.6/lib/redis/client.rb:278:in `rescue in establish_connection': Error connecting to Redis on 192.168.2.31:6379 (ECONNREFUSED) (Redis::CannotConnectError)
from /home/pi/.rvm/gems/ruby-2.2.1/gems/redis-3.0.6/lib/redis/client.rb:

[sasha-id]

Execute it as a root user.

[canedy]

so here is what I tried before and message I received.

sudo thin start -a 192.168.2.31

received following error:
sudo: thin: command not found

also not sure this would make a difference, but i'm running this on raspberry pi 2.

[sasha-id]

gem install thin