I have a survey that existed, and worked fine in Moodle 2.1, that now produces the following error when a user tries to submit the questionnaire:

Coding error detected, it must be fixed by a programmer: clean_param() can not process arrays, please use clean_param_array() instead.

In my Apache error log, I see:

[Mon Dec 26 14:21:55 2011] [warn] [client x.x.x.x] mod_fcgid: stderr: Default exception handler: Coding error detected, it must be fixed by a programmer: clean_param() can not process arrays, please use clean_param_array() instead. Debug: , referer: http://ourwebsite/moodle/mod/questionnaire/view.php?id=106064
[Mon Dec 26 14:21:55 2011] [warn] [client x.x.x.x] mod_fcgid: stderr: * line 717 of \\lib
moodlelib.php: coding_exception thrown, referer: http://ourwebsite/moodle/mod/questionnaire/view.php?id=106064
[Mon Dec 26 14:21:55 2011] [warn] [client x.x.x.x] mod_fcgid: stderr: * line 206 of \\mod\\questionnaire\\questiontypes
questiontypes.class.php: call to clean_param(), referer: http://ourwebsite/moodle/mod/questionnaire/view.php?id=106064
[Mon Dec 26 14:21:55 2011] [warn] [client x.x.x.x] mod_fcgid: stderr: * line 1552 of \\mod\\questionnaire
locallib.php: call to questionnaire_question->insert_response(), referer: http://ourwebsite/moodle/mod/questionnaire/view.php?id=106064
[Mon Dec 26 14:21:55 2011] [warn] [client x.x.x.x] mod_fcgid: stderr: * line 218 of \\mod\\questionnaire
locallib.php: call to questionnaire->response_insert(), referer: http://ourwebsite/moodle/mod/questionnaire/view.php?id=106064
[Mon Dec 26 14:21:55 2011] [warn] [client x.x.x.x] mod_fcgid: stderr: * line 70 of \\mod\\questionnaire
view.php: call to questionnaire->view(), referer: http://ourwebsite/moodle/mod/questionnaire/view.php?id=106064
[Mon Dec 26 14:21:55 2011] [warn] [client x.x.x.x] mod_fcgid: stderr: Default exception handler: Coding error detected, it must be fixed by a programmer: clean_param() can not process arrays, please use clean_param_array() instead. Debug: , referer: http://ourwebsite/moodle/mod/questionnaire/view.php?id=106064
[Mon Dec 26 14:21:55 2011] [warn] [client x.x.x.x] mod_fcgid: stderr: * line 717 of \\lib
moodlelib.php: coding_exception thrown, referer: http://ourwebsite/moodle/mod/questionnaire/view.php?id=106064
[Mon Dec 26 14:21:55 2011] [warn] [client x.x.x.x] mod_fcgid: stderr: * line 206 of \\mod\\questionnaire\\questiontypes
questiontypes.class.php: call to clean_param(), referer: http://ourwebsite/moodle/mod/questionnaire/view.php?id=106064
[Mon Dec 26 14:21:55 2011] [warn] [client x.x.x.x] mod_fcgid: stderr: * line 1552 of \\mod\\questionnaire
locallib.php: call to questionnaire_question->insert_response(), referer: http://ourwebsite/moodle/mod/questionnaire/view.php?id=106064
[Mon Dec 26 14:21:55 2011] [warn] [client x.x.x.x] mod_fcgid: stderr: * line 218 of \\mod\\questionnaire
locallib.php: call to questionnaire->response_insert(), referer: http://ourwebsite/moodle/mod/questionnaire/view.php?id=106064
[Mon Dec 26 14:21:55 2011] [warn] [client x.x.x.x] mod_fcgid: stderr: * line 70 of \\mod\\questionnaire
view.php: call to questionnaire->view(), referer: http://ourwebsite/moodle/mod/questionnaire/view.php?id=106064

I'm using the latest version from the Questionnaire download page. This should be considered a blocker bug as users cannot submit a questionnaire successfully using Moodle 2.2.