OpenVBX One click Install

I installed OpenVBX and everything seems to work fine.

However when I try to write some code using the Rest client, I get an error Call to undefined function get_instance() in …/OpenVBX/OpenBVX/libraries/twilio.php on line 137. I cheched the list of issues at and there is one related to that, but none of the solutions suggested seems to work.

Has any one encountered a similar problem?