the specified file already exists

  Explanation:  An attempt was made  to  create  a  file  but  the
  specified already exists.

  User Action:  If this error  is  returned  while  attempting  to
  perform  an  RMU Backup operation using the Librarian qualifier,
  then it indicates that the backup filename given in the  command
  line  already  exists  in  the  media  manager's storage system.
  Either provide a new unique backup filename or use  the  Replace
  keyword  with  the  Librarian  qualifier  to  instruct the media
  manager to replace the existing backup file with a new one.