That bug has been opened on https://launchpad.net/ubuntu/+source/rhythmbox/+bug/78431

"Binary package hint: rhythmbox

steps to reproduce:
1. insert an audio cd into your cd-drive
2. open rhythmbox
3. go to your cd on the left panel
4. select "copy in your library" (do not know whether it says like that, in Italian is "Copia nella libreria"
5. nothing happens...

looking from the terminal, as I try to copy the cd in the library, rhythmbox reports an error:
(rhythmbox:8341): Rhythmbox-WARNING **: RBLibrarySource impl_paste called when gconf keys unset

and when I open rhythmbox from the terminal, it says
(rhythmbox:8341): Rhythmbox-WARNING **: Unable to start mDNS browsing: Il servizion MDNS non è in esecuzione
(translated: the MDNS service is not in execution)

Version informations:
rhythmbox 0.9.6 on Ubuntu Edgy Eft 6.10, it-IT l10n.
...
>  Thank you for your bug. Could you run "rhythmbox -d" and note to the bug what is printed when you try to copy the CD?
...
When I click on the "copy cd" button (or whatever it says...), the bug is

(rhythmbox:12165): Rhythmbox-WARNING **: RBLibrarySource impl_paste called when gconf keys unset
...
http://librarian.launchpad.net/5689015/log_rhythmbox.txt.tar.gz
output (standard error) of "rhythmbox -d"

"rhythmbox -d" prints out too many things.
I just tried again saving everything on a .txt file.
The only strange thing I found that _could_ be related to this is:

[free_dbus_error] rb-generic-player-source.c:716: finding audio player udi: dbus error: No property info.capabilities on device with id /org/freedesktop/Hal/devices/pci_1106_571_ide_0_0

However, I attach a .tar.gz archive containing the whole log file (originally 1.8 MB). The only action I tried was opening the cd and trying to copy it...

(obviously, I am at your disposal for anything you could need...)"