Observium Network Monitoring Static IP/DNS question?

I am running a turnkey linux Observium VM. Just got it halfway setup yesterday.

Before I set a static IP address today I could add devices with the script. Today I set a static address but and can not add devices. I keep getting this error message...

root@observium /opt/observium# ./add_device.php 192.168.2.11 public v2c 162 tcp Observium CE 0.15.6.6430 Add Device(s) Try to add 192.168.2.11: Could not resolve 192.168.2.11. Devices failed: 1. 

I did not set a DNS server in etc/network/interfaces, do I need to add DNS servers?

auto eth0 iface eth0 inet static address 192.0.2.7 netmask 255.255.255.0 gateway 192.0.2.254 

Add this to the config file?

dns 192.168.0.100