Apple tv 3 after OS 5.1 update stalls streaming movies after one movie

I updated our Apple tv 3 to os 5.1 (on 29 Sep 2012). The update worked without a hitch, except that after playing a single movie using home sharing the apple tv now stalls on the pin wheel loading the second movie. The only thing that seems to fix this is restarting the computer serving the movies. Restarting itunes doesn't work, neither does restarting the apple tv. This problem didn't occur prior to updating the apple tv.

Our machine serving the apple tv is a little old (ibook g4 with itunes 10.6.3) but hasn't changed between updates. The only thing that changed between the update is the apple tv software.

Has anyone come across this problem? Is there a way to go back to version 5.0.2? This is causing some frustration.