Joseph,
I restarted my moodle site after I tried to upgrade the questionnaire module. I get the same error page when clicking the notifications link (twice). The first time clicking it, it says it was successfully upgraded, but the bottom of the page doesnt have a continue button. The second time clicking it, it will give you that error page above. However, I've tried many courses that use the questionnaire module and they seem to work without error. The only error is the notification page. Also, I've tried different themes to see if that helps and it did not.
Thanks.