I thought I would post this in case it might save someone else some time.
On a late 2012 iMac running Mac OS X 10.8.3 (Mountain Lion), Premiere Pro CS6 (v6.0.2) would only play 2-3 seconds from the timeline before stopping. There is a number of reports on the web regarding this with a variety of setups. After trying a number of proposed solutions, I decided to investigate the audio side. Switching to the built-in audio fixed the problem, leading to the Fireface settings. Switching the Clock Mode to Master solved the problem, and switching back to Autosync reproduced the issue.