As he says he is running as root I presume that Linux/Unix is the test case, so i did this:

#!/usr/bin/perl
use Net::Ping;
$p = Net::Ping->new('icmp');
print "She's workin\n" if $p->ping("ns.online.no");
$p->close();
[download]

Prints:

zodiac:/home/perl# ./test1.pl
She's workin
zodiac:/home/perl#
[download]

So it works like a charm running perl version 5.005_03 on kernel 2.2.17 (Debian potato).
Don't know about that inet_aton thingy though..?