FreeBSD 6 - update_virus_scanners weirdness

[Rick Chadderdon]

FreeBSD 6.0
MailScanner  4.51.6
Perl 5.8.8

This is a freshly built server, starting from a minimal FreeBSD 6.0 
install.  I installed MailScanner from ports after manually downloading 
MailScanner-install-4.51.6-1.tar.gz and fixing up the port to reflect 
the newer version of the file.

If update_virus_scanners (or even update_virus_scanners.cron) is run 
manually (as root), everything works fine.  If either is launched as a 
cron job (as root), the f-prot autoupdater fails with the error: 
"Updates download from http://updates.f-prot.com failed. Suspect server 
could not be reached,"  The f-prot-autoupdate script also works fine if 
run directly.  I installed the systutils/rc_subr port since 
update_virus_scanners.cron used it.  Also installed are clamav and 
bitdefender, and their updates seem to work fine from the cron job.  I 
disabled the ipfilter firewall for testing, but the problem still 
occurs.  There is no proxy server.  MailScanner is working great, as always.

Anyone have an idea what's happening here?