I've got the same error but I am under Xubuntu 8.10 and using Thunar.
I don't know if gnome-mount is used on my system.
Here is the error on the terminal :
umount /media/panasonic_
/sbin/umount.hal: Unmounting /media/panasonic_ failed: org.freedesktop.Hal.Device.Volume.UnknownFailure: Cannot remove directory
I've got the same error but I am under Xubuntu 8.10 and using Thunar.
I don't know if gnome-mount is used on my system.
Here is the error on the terminal : .Hal.Device. Volume. UnknownFailure: Cannot remove directory
umount /media/panasonic_
/sbin/umount.hal: Unmounting /media/panasonic_ failed: org.freedesktop