Arduino Zero on Ubuntu "no valid JTAG device"

Hi, I'm trying to use the Arduino Zero on Ubuntu 14 and am getting an error when I try to program the device.

Error: unable to find CMSIS-DAP device
Error: No Valid JTAG Interface Configured

I haven't found anything useful on these errors searching the broader net. Any ideas?

Same problem here with Ubuntu 14.04 LTS. The following fixed the problem so I am now able to upload a sketch.