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.