Windows Media Player cannot play the file because the associated Windows Media metafile playlist does not contain any items, or the playlist is not valid for some other reason.
A metafile is a file that contains information about other files. A Windows Media metafile playlist, which might have an .asx, .wax, .wmx, or .wvx extension, can be used to instruct the Player to play a group of digital media files in a specific order. Metafiles are usually created by a content provider, such as an Internet radio station.
If you created the metafile, verify that it contains items. For information about creating valid Windows Media metafiles, see the Windows Media Player Software Development Kit (SDK) at the Microsoft Web site.