Nova-network with public interface

Hi,

I have four machines running openstack.
Computer #1 is running nova-controller, network, api and compute (yes, its work as a computer node too).
Computer #2 is running another nova-compute node, just it.
Computer #3 is running glance (connected to swift).
Computer #4 is running swift.

The problem is that nova-network is incosistent, each time that i create or start a new instance, i need to try restart the nova-network to instance get access to external network. This bug happen just on nodes that are running out of controller machine, like instances on computer #2.

Instances running on nova-computer that runs on Computer #1 doesn't bug and doesn't need nova-network to works.
Instances running on nova-computer that runs on Computer #2 have the bug and need to restart the nova-network (on computer #1) to get it works.

OpenStack Version: 2011.3 (2011.3-nova-milestone-tarball:tarmac-20110922115702-k9nkvxqzhj130av2)

Nova.conf:
--ca_path=/var/lib/nova/CA
--cc_host=192.168.100.241
--daemonize=1
--dhcpbridge=/usr/bin/nova-dhcpbridge
--dhcpbridge_flagfile=/etc/nova/nova.conf
--ec2_url=http://192.168.100.241:8773/services/Cloud
--fixed_range=10.0.0.0/24
--flat_network_bridge=br100
--flat_interface=eth0
--flat_network_dhcp_start=10.0.0.2
--instances_path=/var/lib/nova/instances
--keys_path=/var/lib/nova/keys
--libvirt_type=kvm
--lock_path=/var/lock/nova
--logdir=/var/log/nova
--network_manager=nova.network.manager.FlatDHCPManager
--network_size=8
--routing_source_ip=192.168.100.241
--public_interface=eth0
--rabbit_host=192.168.100.241
--s3_host=192.168.100.241
--sql_connection=mysql://nova:cpca@192.168.100.241/nova
--verbose=True
--vnc_enabled=True
--vncproxy_url=http://192.168.100.241:6080
--vncserver_host=0.0.0.0
--vnc_token_ttl=300
--networks_path=/var/lib/nova/networks
--state_path=/var/lib/nova
--scheduler_driver=nova.scheduler.simple.SimpleScheduler
--iscsi_ip_prefix=192.168.
--image_service=nova.image.glance.GlanceImageService
--glance_host=192.168.100.242
--glance_port=9292
--glance_api_servers=192.168.100.242:9292

Logs are attached.