If you are using Vuforia 5.5.9, you should be able to select these settings in the ARCamera inspector:

- Eyewear Type = Video See-through

- Stereo Camera Config = Vuforia

- Viewer Type = drop down list with several values, including Cardboard v1 (Google)

I'm having the same problem, is there anyone who could shed some light on this issue?

Hi, 

I am too getting same error. And my system requirements,

Windows 7 service pack 3,

unity 5.3.0 pro version 64 bit,

Vuforia 5.5.9

Thanks,

Nagaraj