database monitor is not running

  Explanation:  The database monitor process is not running or has
  abnormally  terminated.   There  may  also be a problem with the
  mailbox used to communicate with the database monitor.

  User Action:  Check the system to determine whether or  not  the
  database monitor process is actually running on your system.  If
  the database monitor process does not appear to be running, have
  your  database  administrator  start the monitor, and try again.
  If the database monitor process appears to be running  properly,
  then  the  problem  may  be related to the mailbox by which user
  processes communicate with the monitor process.  Make  sure  the
  logical  <fac>$MAILBOX_CHANNEL  resides  in a logical name table
  accessible to all  users,  typically  the  LNM$PERMANENT_MAILBOX
  name  table.   If  the monitor abnormally terminated, a bugcheck
  dump will normally be written to the monitor  log.   Search  the
  monitor  log  for  a  string of five asterisks (*****) using the
  SEARCH/WINDOW command.  You  will  see  a  line  with  a  format
  similar  to  this:   *****  Exception  at <address> :  <database
  module name> + <offset>  %facility-severity-text,  <error  text>
  The  exception  line  will be followed by one or more additional
  errors that will help you to determine what caused  the  monitor
  process   to   fail.    Typically,  the  problem  is  caused  by
  insufficient  quotas  or  system  resources.    However,   other
  possible   causes   include  misdefined  or  undefined  filename
  logicals.  Depending on the  cause  of  the  problem,  take  the
  appropriate action.  If you are uncertain of what to do, contact
  your Oracle support representative for assistance.