audio no video - gspot and avicodec say MPEG-1 Layer 3

Hi, I used both AVIcodec and GSpot and it doesn’t give me a codec name. It tells me the file is MPEG-1 Layer 3, but that’s it. I can hear the audio when I play it, but no video.(And I have Kazaa, DivX, Win. Media Player) Any thoughts?

(late answer, I know)
It means it’s an mp3, not a video file. Some weirdoes do that on file sharing networks (maybe to avoid the RIAA?)