volgens Matteo Scaramuccia.
Hi Jeff,
that error is part of those returned by Moodle and could be related to the way it manages CSRF vs PHP session files.
My guess - I'm missing details about your PHP-on-Windows exact setup and if you're using the Moodle Legacy File sessions - is that your PHP setup is not allowed to write session files due to lack of the right file permissions set. Please, check the PHP info to identify the context Moodle is running on and where the session folder (session_save_path) has been defined: there, add Modify permission according to the user your pool is running with.
To have an overview of the most common issues with Moodle setup, please use the Health Center too.
HTH,
Matteo