FATAL 1: LWLockAcquire: can't wait without a PROC structure

Hi,

I get the following msg "FATAL 1:  LWLockAcquire: can't wait without a 
PROC structure" in the log file about once a day and every user is 
kicked out of the database.

Running on a single cpu amd with Redhat Linux 7.2 kernel 2.4.7-10 and 
the postgresql-7.2.1-5 rpm's

NB I tried running it on a dual cpu smp machine running 2.2.18* and 
there I got this msg far more frequently about once an hour.

usaly 30-50 connections during the daytime.

:-) help!

regards

fredrik chabot