PGSQL ERROR: FATAL: terminating connection due to administrator command

I have a PostgreSQL 8.2.6 on FreeBSD 6.3 (but the described behavior
appears during several earlier minor versions as well) - which powers a
php based web application. What I experience is the message (below)
which appears during the first 5-7 clicks after the database has been
cleanly imported (dropped and imported) -

PGSQL ERROR: FATAL: terminating connection due to administrator command
server closed the connection unexpectedly
    This probably means the server terminated abnormally
    before or while processing the request.

The message does not appear on every click. It can appear on the 1st,
then not on the 2nd, then on the 3rd and so on. After few more clicks
everything goes well until the next import.

I could not find anything meaningful in the logs...

Has somebody else experienced anything similar?

Iv