For some reason, upgrading to LabVIEW 8.6.1 can cause the "VI Server: Exported VIs" settings to get reset in a way that prevents VIPM from being able to connect. To fix this, do the following:
LabVIEW's VI Server permissions are not configured correctly for VIPM.
In the LabVIEW options dialog (Tools>>Options) go to the "VI Server: Exported VIs" page and ensure that you entered a value of "*" (see below).