In kubuntu 12.04 with 2.6.0 of amarok and the latest version of the gstreamer backend amarok was successfully playing cds. I've upgraded to 12.10 this week and cds no longer play, all the package versions appear to be the same (but from the distro repos rather from backports) so still 4.6.2 of gstreamer.
When I insert a cd it appears in the collection and I can drag tracks to the playlist but if I double click them (in the playlist) or select play, nothing happens the track will not start and the play button doesn't change to pause.
Not sure if this is an amarok issue or the kubuntu packaging of 2.6.0?  I have a number of open bugs with cds - with this bug I can't verify the fixes to the other ones...!

Reproducible: Always

Steps to Reproduce:
1. See details, insert cd drag track to playlist and click play

Actual Results:  
Here's the output from the command line of dragging a track to the play list and attempting to play:
~$ amarok
QDBusConnection: session D-Bus connection created before QCoreApplication. Application may misbehave.
QDBusConnection: session D-Bus connection created before QCoreApplication. Application may misbehave.
Fontconfig warning: "/etc/fonts/conf.d/50-user.conf", line 9: reading configurations from ~/.fonts.conf is deprecated.
QWidget::insertAction: Attempt to insert null action
Object::disconnect: Unexpected null parameter
Object::disconnect: Unexpected null parameter
********************************************************************************************** 
** AMAROK WAS STARTED IN NORMAL MODE. IF YOU WANT TO SEE DEBUGGING INFORMATION, PLEASE USE: ** 
** amarok --debug                                                                           ** 
********************************************************************************************** 
~$ link XMLID_9_ hasn't been detected!
link XMLID_9_ hasn't been detected!
link XMLID_9_ hasn't been detected!
link XMLID_9_ hasn't been detected!
Could not resolve property : linearGradient5167
Could not resolve property : linearGradient3563
Could not resolve property : linearGradient3563-3
Could not resolve property : linearGradient3563-3


Expected Results:  
I'd expect cds to play 

With other music apps cds play correctly (I tried with audacious)