Missing Audio codec

I put a post up on the microsoft message board about
missing the ADPCM Codec. Your suggestion was to reinstall
media player 9. I did that, but it didn't help. I tried
playing the video in DivX Player 2.1, and it gives me the
error "The file contains the following type of data:
Audio Data: Tag 2". It says I need to install another
codec to get the audio to work. Media Player tries to
download a codec from it's server, but ends up coming up
as an error. Do you have any suggestions?