VMS Help  —  RMU72  RMU_ERRORS, AREABUSY
  usage of storage area <str> conflicts with a co-user

  Explanation:  You attempted to ready an  area  that  is  already
  being   accessed  by  another  user,  and  that  usage  mode  is
  incompatible with the usage mode you requested.

  User Action:  Wait until  the  storage  area  you  requested  is
  available,  and  try  again,  or  ready  the  area with the WAIT
  option.
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