Video but no sound in Studio Subtitling.

So, I have opened my subtitling project, with my .srt template, TM and MT are working, I can see the video playing, but there is no sound. It is an ordinary Quicktime video with AAC and H.264 codecs. It plays in my other applications so it is not a question of missing codec. Being able to hear the voices I am translating would be really nifty, so I am grateful for any suggestion. Thanx. Daniel