I downloaded them again but it made no difference.

I had no problem in extracting the files using Winzip.  But when tried to play the file using WMP, a message box was popped up with this message: An audio codec is needed to play this file.  To determine if this codec is available to download from the Web, click Web Help.

I have no problem play the same mp3 file using Real Player.

Thanks anyway for your effort!