realplayer can't play files burned to dvd

stephenchw

can someone help? my real player can't play rm files that i burned to a dvd disk.  the orginial video files stored on the hard disk can be played perfectly.  i burned the files to a dvd disk for backup, but the files can't be played from the disk; i copy it back to the hard disk but still can't play.  the software i used to burn the files was nero 7. i used "create data file" to backup my video files.( is this the reason why?)  my computer is running on windows xp with service pack 2; and i m playing my rm files with real player version 10.  thank u very much