Database update problem from crontab on ubuntu server

Hi,

I have daily cron jobs for database update, which where working fine on
Fedore Core 6. No I move it on Ubuntu Server 7.10 and postgres gives error:

"unexpected EOF on client connection"

while update running from cron. If I run this update manually from root
user - it works fine. Here is update command:

su -l postgres -c "gunzip -c /backup/rms.gz | psql rms"

Can somebody give any suggestion?

Thanks,
David