The subject error is produced by Media Player versions 6.1, 6.4, and 7.
"This error message can occur for any of the following reasons:
The media file you are attempting to play is not a supported file format for Windows Media Player, or the media file uses a codec that is not supported by Windows Media player.
You need to update to the latest version of Windows Media Player.
The Quartz.dll file is missing or damaged.
A registry key is missing or damaged.
The codec needed to play the media file is missing or damaged."