iptables in Virtual Machine Manager

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/host.py", line 401, in start_network
    net.start()
  File "/usr/share/virt-manager/virtManager/network.py", line 97, in start
    self.net.create()
  File "/usr/lib/python2.6/dist-packages/libvirt.py", line 866, in create
    if ret == -1: raise libvirtError ('virNetworkCreate() failed', net=self)
libvirtError: internal error '/sbin/iptables --table filter --delete INPUT --in-interface virbr0 --protocol udp --destination-port 69 --jump ACCEPT' exited with non-zero status 1 and signal 0: iptables: Bad rule (does a matching rule exist in that chain?).