<<<FCP A/V >>>
The Log and Capture panel itself has settings for Audio, Video, or Both. You need to catch it while the panel is open.
There is another possibility. Do you have a fancy-pants video capture card in addition to the straight FireWire HDV capture? We have one card that on occasion will assume incorrect sound settings.
You do know absolutely that you have sound, right? You can hear the boidies choiping through headphones?
Koz