nagios & PG

Hi Gurus,
We are running Nagios version 3.0 to monitor a PG v 8.3.6  database
server  RHES 5, nagios is trying to  open a  tcp connection on port 5432 .
every time the monitoring job is running PG is logging  the following
message in errorlog , how can we stop this message?
2009-08-04 12:40:31 PDT [16504]: [1-1] LOG:  incomplete startup packet
2009-08-04 12:45:31 PDT [16610]: [1-1] LOG:  incomplete startup packet

Thank you
Isabella

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