Deadlock on Linux

Hi,
I am running Postgres 6.3.2 on Caldera Linux 2.0.35. There are a few
scripts written in Perl using Pg.pm which tune up the database nightly.
They've been running for more than three months. However, since last
month one of the scripts is failing to execute, giving the following
message
NOTICE: Deadlock detected -- See the lock(l) manual page for a possible
cause.

There is no entry for lock in section 1 of the man on my system. There
is one entry however for lock which says that this call is not
implemented in the Linux kernel 1.2.4 and it returns a -1 always.

Does anyone have any idea what is happening? The script in question runs
fine when I run it independent of the cron.

Thanks for your help in advance,
Anand Surelia.