One thing that you might try — a long shot — is a different USB cable. (The WaterColorBot is extensively tested before shipping, but comes with a new USB cable.)
I am following up on the software side, to see what else we might be able to try from a diagnostic standpoint.
In the mean time, you might consider giving the WaterColorBot’s Inkscape driver a try– it should get you up and running to at least try out the machine.
