I am running Kubuntu 12.10 x64. When loading audio files in a music project, I try to right click on the audio files added to the project, and notice "Play Track" is grayed out.

A quote from bcooksley on the issue:
I tested the playback of audio in K3b and found that it not only did not use Phonon, but the system it was using totally bypassed Pulseaudio.
Please file a bug report against K3b, as it should be using Phonon for this functionality (and if it is using Phonon, then it is doing it extremely wrongly). 

Reproducible: Always

Steps to Reproduce:
1. Start audio project.
2. Load audio in to project.
3. Right click on audio track and try to "play Track"
Actual Results:  
Play track is greyed out and not bale to be clicked.

Expected Results:  
Play track should play back the audio file.