[libvirt] Unable to open virt-manager

[Doron Fediuck]

Hi,
I'm trying to work remotely on a server with F12, using vnc.
When I start virt-manager, I do not get the authentication popup, and instead I get this message:

Unable to open connection to hypervisor URI 'qemu:///system':
authentication failed
Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/connection.py", line 872, in _try_open
    None], flags)
  File "/usr/lib64/python2.6/site-packages/libvirt.py", line 102, in openAuth
    if ret is None:raise libvirtError('virConnectOpenAuth() failed')
libvirtError: authentication failed

RPM versions:
libvirt-0.7.1-15.fc12.x86_64
libvirt-client-0.7.1-15.fc12.x86_64
python-virtinst-0.500.1-2.fc12.noarch
virt-viewer-0.2.0-1.fc12.x86_64
virt-manager-0.8.2-1.fc12.noarch
virt-ctrl-1.0.1-4.fc12.x86_64
libvirt-python-0.7.1-15.fc12.x86_64

Any idea what causes the popup to fail ?