Backup set file number <num>, the first backup file specified,is
  not  the  first  file of the backup set.  Specify all the backup
  set files ordevices in the correct order.

  Explanation:  The first backup set file specified  was  not  the
  first backup set file specified by the backup command.

  User Action:  Repeat the restore, specifying all the backup  set
  files in the correct order.