Adobe After Effects 6 - imported MPG has no audio

Hi

I just created a new project in After Effects 6 and imported an MPG clip with audio, but despite toggling on the audio switches etc the clip has no sound. The visual stuff is fine but I can't figure out why the audio won't work. By the way I have checked the audio on other devices and with other playback programs and it works fine.

Please can you tell me what I need to do to get the audio to work.

Thanks

Nicky