Movie maker sound lost, but in original

hi, I made an avi with my digital camer (with sound)
uploaded to the pc, the it plays properly.
however, when i load it into movie maker, although it
plays with sound, when i drop into the timeline, it loses
its sound . the audio track in the timeline is full of
the audios wiggly line, but i can only get the audio in
the original.
even when saved, the new avi/mpg has no sound in any
player???