Questionnaire (plugin)

We run Moodle 1.9.7 on Win 2003 IIS 6.0 MS-SQL

The 1.9 version of questionnaire installed no problems but when I tried to load the latest version I get this error (amongst many others)

ALTER TABLE DROP COLUMN public failed because one or more objects access this column.

ALTER TABLE mdl_questionnaire_question DROP COLUMN "public" (full-text attached)

and the upgrade goes into a loop you can't get out of without removing the questionnaire directory.

Same error when I try to upgrade Moodle to the latest version.

Any help appreciated.