[libvirt] libvirtd can not start up

Hi all: I met a issue during boot libvirtd.When I use "libvirtd --daemon " , libvirtd didn't start up. And I am using the latest libvirt source code . Here is the libvirtd.log /usr/local/var/log/libvirt/libvirtd.log 2012-06-15 06:35:04.230+0000: 16193: info : libvirt version: 0.9.12 2012-06-15 06:35:04.230+0000: 16193: error : virStateInitialize:781 : Initialization of NWFilter state driver failed 2012-06-15 06:35:05.079+0000: 16193: error : daemonRunStateInit:752 : Driver state initialization failed anybody konws what 's going on ? Thanks Lin Qing.