Slackware 12 - A security policy in place prevents this sender...

Errore:
A security policy in place prevents this sender from sending this
message to this recipient, see message bus configuration file (rejected
message had interface "org.freedesktop.Hal.Device.Volume" member "Mount"
error name "(unset)" destination "org.freedesktop.Hal")

Soluzione:
aggiungi l'utente nel gruppo plugdev
riavvia il computer