Hello. When an ERR shows up in the Cur column, that means that the most recent sample in the sample set you're looking at was lost - and never returned. That's a lost packet, and shows up in the packet loss column.

We cover the values in our manual, here:

http://www.pingplotter.com/manual/standard/theinterfacegraphs.html

The screenshot you posted looks a bit like there's some underlying route changes (unfortunately, route changes are hard to represent well in a static screenshot like this).

We might be able to offer a bit more explicit advice if you email a .pp2 file (File -> Save Sample Set..., then attach it to an email to support@pingplotter.com) - which captures all the route changes. From there, we can look for patterns and post back some recommendations here.

Best wishes,
Pete