Do you by any chance have the latest nVidia drivers installed? If so, please roll back to an older version.
The latest nVidia drivers have issues with the DK2, not only with vorpX. One of them being to force the display to a refresh rate that causes the DK2 to display two images like shown in your picture. General consensus is to not use the latest nVidia drivers with the DK2.
If that is not the issue, please make sure to have vorpX only enabled while playing games not made for VR. Your photo looks like the Oculus demo scene, so double images would be normal, since vorpX is added on top of the native stereo rendering.