Hello!

It looks as if your router may be having some trouble servicing multiple ICMP echo requests. Something to try here would be to configure PingPlotter to only do one outstanding request at a time. We've got a bit of documentation that goes through the step-by-step process on how to do this, which can be found here:

http://www.nessoft.com/kb/22

Please let us know if you have any other questions, or need any further assistance!

-Gary