Perl + Determine active connections on Pg 8.0.x and Pg 8.2.x

Hello,

We have Pg 8.0.x and Pg 8.2.x on 2 separate Linux servers. We have a perl script (perl 5.8.7, DBI-1.48/DBD::Pg-1.49) that connects to each database to determine if there are active connections.with the following query.
SELECT count(*) from pg_stat_activity;

The above query always returns 0 rows for Pg 8.0.x and 1 row for Pg 8.2.x.

When we connect to the database using psql client, the above query returns 1 row for both the databases.

Does anyone has an idea what could be the issue? Is there any other way to determine active connections in the database?

Thanks for all the help!