Getting FATAL: terminating connection due to administrator command

Hi

Since some days we are getting the above message.

The system is a current CentOS 5.5, x86_64, Postgresql 8.4 as it comes with the packages postgresql84,
postgresql84-libsetc. PostGIS is enabled, as it comes from http://www.argeo.org/linux/argeo-el.
 

The error message appears from time to time. The exact same request, coming from a PHP applications, sometimes works,
sometimesfails. This happens in different points of our applications, tipically, but not only, when large data portions
arequeried, as in geometric queries, using PostGIS.
 

The server is only slightly loaded.

Also in the PostgreSQL logs we get:

FATAL:  terminating connection due to administrator command

repeated multiple times.

The server is from Dell, Dell's hardware monitoring, OpenManage, says that the hardware, in particular memory and disk,
areok.
 

We do have a nearly identical server, with the identical version of PostgreSQL/PostGIS, but that was last updated one
ortwo months ago and which is intensly used as our testing and development server, which never gave us the same error
message.

Where could I start to troubleshoot this problem.

Peter Hopfgartner