Membership Plan Sign Up Links not working

I have setup 3 plans and a module displaying only one plan ID. As well as a layout pricing table showing 3 plans.

Problem is that none of the sign up links work. I switched on Debug Mode and get the following error:

Warning: require_once(/var/www/public_html/mydomain.com/libraries/joomla/document/html/renderer/head.php): failed to open stream: No such file or directory in /var/www/public_html/mydomain.com/templates/probiz/error.php on line 28 Fatal error: require_once(): Failed opening required '/var/www/public_html/mydomain.com/libraries/joomla/document/html/renderer/head.php' (include_path='.:/usr/share/php') in /var/www/public_html/mydomain.com/templates/probiz/error.php on line 28

Any ideas whats going on. I tried changing to the default joomla theme but no joy

Thanks

Hello Stephen

Look like there is something special on your site causing the error. Please submit a support ticket sending us:

- Super admin account of your site
- Link to the page which we can see this error

We will check to see why the issue happens and get it corrected for you

Regards,

Tuan