Thanks for the information.

I have determined that the cause of the crash is related to using Win32::OLE in the same script. This script crashes too:

use Net::Ping;
use Win32::OLE; # or use Win32::OLE::Variant;
$p = Net::Ping->new();
print $p->ping($hostname);
[download]

For the immediate period, I have found that by changing the protocol to "icmp", I don't get the error.
Setting the protocol to "external" doesn't cause the crash either, but occasionally returns false even for hosts that are alive.