It's seems weird to be advocating another non-Perl solution in so short a timespan, but this is something done obscenely easy with a shell script if your ping binary has appropriate permissions (they usually do)...
PING='/bin/ping -c 5' # FreeBSD/Linux
#PING='/usr/sbin/ping' # Solaris
FETCHMAIL='/usr/local/bin/fetchmail -s -t 60'
$PING $hostname 1>/dev/null 2>&1 \
If you absolutely must write something in Perl, then I second blm's suggestion of Net::Ping::External (alt.).