Dear Peter,

Hope you are doing good.

The issue is because of the incompatibility of Web Driver with Mozilla Firefox Version.

Please uninstall the Mozilla Firefox Browser from your System, download the Firefox 40.0 from the below link and install it:

http://filehippo.com/download_firefox/download/b284df5bc9435d89bdab96444f41f44d/

Now, try to execute the Selenium Code. Please try this and let us know if the issue persist.