Vista - media Player 11 burns duplicates of each song on playlist

I am not a novice user but this one really is a puzzle. When ever I use
Media player to burn songs to a blank cd it creates duplicate songs on the
CD. Sometimes they are one after another and sometimes seperated. I have
checked the playlists and in some cases MP 11 has actually modified the list
and duplicated songs on the list in other cases the lists are 'clean' with
only one copy of each song. I have cleaned up [removed duplicate songs]
from the playlist and tried burning again with the same problem...I cant
begain to count the CD's wasted. Any help would be appreciated
--
Robert