I had a centos VM that I hadn't used in a while, I think I cloned it from another version.

When I came to use it again I had no network andtrying to start the network I got the error message in the title.

There seem to be a few issues

Firstly netowrking isn't endabled by default

http://wiki.centos.org/FAQ/CentOS6#head-b67e85d98f0e9f1b599358105c551632c6ff7c90

Secondly the cloned image appears to get a different mac address for the network card, but theconfig doesn't auto detect this

Thirdly the new machine seemed to have eth1 instead of eth0

and finally I needed to enable dhcp

What this meant was copying the new mac address from the virtualbox network settings tab (inserting a colon every second charecter  to match the format required)

I placed this in both 

/etc/udev/rules.d/70-persistant-net.rules

and  

/etc/sysconfig/network-scripts/ifcfg-eth0

Where I also set 

ONBOOT="yes" 
BOOTPROTO="dhcp"

Finally /etc/init.d/networking restart got my network up