I assume you are using a DK1? Apparently a few DK1 users are experiencing this. Please try to (re)install the latest Oculus runtime (0.41) from the Oculus website. Normally it should have been installed with vorpX, but maybe that failed in your case.
If that doesn’t help, please send a mail to support |at| vorpx com to get a rollback option to vorpX 0.64.