[libvirt] fail to run virsh

Hi, I installed libvirt (cvs version), and can confirm that libvirtd is running. However, virsh failed to work. I got the below message when running virsh with debugging information. How to fix this problem? Many thanks, Jun # LIBVIRT_DEBUG=1 virsh DEBUG: libvirt.c: virInitialize (register drivers) DEBUG: libvirt.c: virConnectOpenAuth (name=(null), auth=0xb7f53b84, flags=0) DEBUG: libvirt.c: do_open (Probed qemu:///system) DEBUG: lxc_driver.c: lxcCheckContainerSupport (clone call returned EINVAL, container support is not enabled) DEBUG: libvirt.c: do_open (Using qemu:///system as default URI, 1 hypervisor found) DEBUG: libvirt.c: do_open (name "qemu:///system" to URI components: scheme qemu opaque (null) authority (null) server (null) user (null) port 0 path /system ) DEBUG: libvirt.c: do_open (trying driver 0 (Test) ...) DEBUG: libvirt.c: do_open (driver 0 Test returned DECLINED) DEBUG: libvirt.c: do_open (trying driver 1 (QEMU) ...) DEBUG: libvirt.c: do_open (driver 1 QEMU returned DECLINED) DEBUG: libvirt.c: do_open (trying driver 2 (Xen) ...) DEBUG: libvirt.c: do_open (driver 2 Xen returned DECLINED) DEBUG: libvirt.c: do_open (trying driver 3 (OPENVZ) ...) DEBUG: libvirt.c: do_open (driver 3 OPENVZ returned DECLINED) DEBUG: libvirt.c: do_open (trying driver 4 (LXC) ...) DEBUG: libvirt.c: do_open (driver 4 LXC returned DECLINED) DEBUG: libvirt.c: do_open (trying driver 5 (remote) ...) DEBUG: remote_internal.c: doRemoteOpen (proceeding with name = qemu:///system) libvir: Remote error : No such file or directory DEBUG: libvirt.c: do_open (driver 5 remote returned ERROR) DEBUG: hash.c: virUnrefConnect (unref connection 0x806b588 qemu:///system 1) DEBUG: hash.c: virReleaseConnect (release connection 0x806b588 qemu:///system) error: failed to connect to the hypervisor