Errors in DB2 8.0 db2diag.log
Check the following if it's applicable to your case:
ECONNREFUSED (79) "Connection refused" message in the db2diag.log for the db2hmon process.


  Cause
  
  The DB2 Health Monitor periodically wakes up and checks for a
  connection to the DB2 administration server (DAS).  
  
  Resolving The Problem
  
  This type of error is reported when the DAS (DB2 administration
  server) is not active. When the health monitor wakes up it checks for
  a connection to the DAS. In this case the connection is refused as
  either the DAS does not exist or it is not started.