br0 for kvm is not working on Hardy

[James Dinkel]

I just did a fresh install and update of Ubuntu Server 8.04.
Following the server documentation, I'm changing my network config so
I can have a bridge interface.  The network works fine by default, but
when I change to the following configuration, I get an error:

--------------------------------
# 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
iface lo inet loopback

# The primary network interface
#auto eth0
#iface eth0 inet dhcp

auto br0
iface br0 inet static
        address 192.168.5.18
        network 192.168.0.0
        netmask 255.255.248.0
        broadcast 192.168.7.255
        gateway 192.168.3.1
        bridge_ports eth0
        bridge_fd 9
        bridge_hello 2
        bridge_maxage 12
        bridge_stp off
--------------------------------

The error I get is a bunch of lines saying:
"br0:  ERROR while getting interface flags:  No such device"
and then one final line saying:
"Failed to bring up br0."

Any ideas?

thanks,

James