Ubuntu Servers :: Eth0 Doesn't Start After Interfaces Modified

I have three VMs (VMWare Server 2) all running Ubuntu Server 10.04. (one I asked to be a samba share from the outset, the others are blank server installs, no pre-config)

I follow the layout in the community documentation regarding setting up firewall rules through iptables. I.e. I create a file called iptables.rules and place it in /etc. I then modify the /etc/network/interfaces file to look like this:

Code:
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo

[Code].....

However this third one I have reinstalled Ubuntu 3 times now, and every time as soon as I modify the /etc/network/interfaces file, eth0 fails to start up (is not visible in ifconfig, only the loopback adapter), and no networking works.

I have tried reducing the iptables.rules file (which is a carbon copy across all machines anyway) to a basic accept all rule, and it still doesn't like it. As soon as I remove those two extra lines in the interfaces file, the network starts up no problems and eth0 is there.