Here's something that might help. I had the same problem and was given this solution by someone in this forum.
Code:
def finishedActions(avatar):
global avatarCount
if isinstance(avatar,viz.VizAvatar):
WaitThenFreeze = vizact.sequence( vizact.waittime(avatar.getduration(10)-.85), vizact.speed_node(0) )
avatar.execute(10)
avatar.clear(viz.ALL)
avatar.clear(viz.CURRENT_ACTION)
avatar.add(WaitThenFreeze) #Add the action to the avatar