Error messages created by plugin

Hi, I’ve been using a Contact Form 7 – PayPal plugin and everything has worked great until I updated the plugin to its latest version. It creates the following error messages in the dashboard on my site and some of this error message appears in the header of my site. My only option has been to delete the plugin! I’m with Tsohost and it’s not a custom server. I’ve posted in the support forum for the plugin and messaged the author but I’m pretty desperate to get fixed as my booking page doesn’t work at the moment. Just wanted to know based on the pic and error messages if this is something to do with the theme? Thanks so much ??

Here’s an image of the error

Warning: session_start(): Cannot find save handler ‘memcache’ – session startup failed in /var/sites/b/babyworldandme.co.uk/public_html/wp-content/plugins/contact-form-7-paypal-add-on-pro/paypal.php on line 125

Warning: Cannot modify header information – headers already sent by (output started at /var/sites/b/babyworldandme.co.uk/public_html/wp-content/plugins/contact-form-7-paypal-add-on-pro/paypal.php:125) in /var/sites/b/babyworldandme.co.uk/public_html/wp-admin/includes/misc.php on line 1114