Excon nonblock is not supported by your OpenSSL::SSL::SSLSocket


I am trying to install knife ec2 on Ubuntu 12.04LTS and can not find what is
going wrong.
When I try a simple ‘knife ec2 server list’, it reports ‘Excon nonblock is not
supported by your OpenSSL::SSL::SSLSocket’.

I have tried Googling and lots of different variations of Ruby versions without
much luck.
I have installed all dependencies on this page:
and have set up AWS credentials.

Does anyone know what might be wrong?

Thank you.