What does the error message “The tablet driver is not running” mean and how do I fix it?

This error message is given when the Wacom Professional Service is not running due to a service crash.

To resolve this issue, please restart your computer. If you receive the same error message, please uninstall and reinstall the driver with the current version. If the issue continues, please contact Wacom Support.

Steps to uninstall and reinstall the driver can be found here