this report has been filed here:

https://bugs.edge.launchpad.net/ubuntu/+source/rhythmbox/+bug/530372

rhythmbox version is: 0.12.8

"I'm unable to change the tags of the songs, message is:

(rhythmbox-metadata:2475): GStreamer-CRITICAL **:
Trying to dispose object "id3demux0", but it still has a parent "pipeline".
You need to let the parent manage the object instead of unreffing the object directly.

(rhythmbox-metadata:2475): GStreamer-CRITICAL **:
Trying to dispose object "id3v2mux0", but it still has a parent "pipeline".
You need to let the parent manage the object instead of unreffing the object directly.

(20:06:14) [0x9643068] [rb_metadata_bus_handler] rb-metadata-gst.c:676: message of type state-changed from giostreamsink0
(20:06:14) [0x9643068] [rb_metadata_bus_handler] rb-metadata-gst.c:676: message of type state-changed from typefindelement0
(20:06:14) [0x9643068] [rb_metadata_bus_handler] rb-metadata-gst.c:676: message of type state-changed from urisrc
(20:06:14) [0x9643068] [rb_metadata_bus_handler] rb-metadata-gst.c:676: message of type state-changed from pipeline
(20:06:14) [0x9643068] [rb_metadata_bus_handler] rb-metadata-gst.c:614: got error message from typefindelement0
(20:06:14) [0x9643068] [rb_metadata_bus_handler] rb-metadata-gst.c:630: caught error: Unable to create tag-writing elements
(20:06:14) [0x9643068] [rb_metadata_dbus_save] rb-metadata-dbus-service.c:279: metadata error: Unable to create tag-writing elements
(20:06:14) [0x9643068] [send_error] rb-metadata-dbus-service.c:88: attempting to return error: Unable to create tag-writing elements
(20:06:14) [0x9c8aae8] [default_sync_metadata] rhythmdb.c:4779: error saving metadata for file:///media/cons/Music/Green%20Day/(2002)%20Pop%20Disaster%20Tour%202002/Green%20Day%20-17-%20Good%20Riddance.mp3: Unable to create tag-writing elements; reloading metadata to revert"

full log here:

http://launchpadlibrarian.net/49497310/rhythmbox-debug.txt

Thanks!,