Setting up Casperjs

I have installed Casperjs on my raspberry-pi following this tutorial: http://blog.daviddemartini.com/installing-casperjs-on-raspberry-pi/

I need it to tests the AJAX of my Django app so next I will have to insatll Django-Casper.

Everything worked fine but when I tried to run $ casperjs I've an error TypeError: Attempting to change the setter of an unconfigurable property.

I have searched a way to fix this issue but with no luck. Has anyone encountered the same issue?