[libvirt-users] error: Unable to add port vnet1 to OVS bridge ovsbr: Operation not permitted

I am using libvirt version 0.9.13 with Ubuntu 12.10 When I try to start a VM with an openvswitch bridge interface I get the error: error: Failed to start domain kvm113-2 error: Unable to add port vnet1 to OVS bridge ovsbr: Operation not permitted Here is my bridge configuration: <interface type='bridge'> <mac address='52:54:00:c7:db:d2'/> <source bridge='ovsbr'/> <virtualport type='openvswitch'> <parameters interfaceid='40e21558-217c-d8ef-c9a9-5275fa4b4a46'/> </virtualport> <model type='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </interface> This configuration previously worked fine. Request your help and insights. WIth best regards Radhika