[libvirt] error: failed to connect to the hypervisor

Hello, I have installed libvirt-bin 0.6.1 on the ubuntu 9.04. When I run "virsh -c qemu:///system list", I get this error: ---------------------------------------------------------------------------- unable to connect to '/var/run/libvirt/libvirt-sock': Permission denied failed to connect to the hypervisor ----------------------------------------------------------------------------- Then I search in the Internet, it may be a bug of version 0.6.1. So I update libvirt-bin to version 0.6.3, but I still get a error: --------------------------------------------------------------------------------- root@forest:/home/zli# virsh -c qemu:///system list error: failed to connect to the hypervisor ---------------------------------------------------------------------------------- I have no idea about the reason. Any helps? Regards Zhentao