Cannot login to local host after plugin install

I have successfully loaded xammp and wordpress. I also increased the max file upload and max file post size to 1024m in PHP.ini

I then installed the Total theme and that worked fine.
I then installed some sample data which required the installation of Contact Form 7 and that was not successful. I logged out.

I then tried to login and am know receiving the error message ”
Fatal error: Cannot use $this as parameter in C:\xampp\htdocs\wordpress\wp-content\themes\Total\framework\3rd-party\contact-form-7.php on line 37″

and now cannot login in to disable this plugin.

How do I fix this?
Does this suggest an incompatible plugin or something else?

thanks for any help