Hi Lord:

I am having somewhat of a problem with my Windows Media Player. When I tried to preview the downloading movie or even after full download, I get a message that reads: Windows Media player cannot play this file. It is missing one or two codecs: What does that mean? Also, I tried selecting Limewire Media Player to be default player by checking the little box, but still doesn't work. Thank you for your reply.

It means that WMP is missing some information that it needs to be able to play those file types. You'll find links to codec packs below & also a link to VLC player which has built in codecs & can play most things
Codecs & VLC
(the XP codec pack is good for WMP)

Open your saved folder (outside of LW), right click on a file > open with > choose program > choose WMP. Tick 'always use the selected program to open this kind of file' > OK.
That should make WMP your default player!