it is important to use the right feedback-module for the related moodle-version.
You should clean up your system and new install the feedback-module.
Go into the "Site Administration" -> "Modules" -> "Activities" -> "Manage activities" and delete the feedback-module (note: all existing feedbacks on installed courses will be deleted)
After that you should look at the database whether there still are some feedback-tables. If it is so you can drop all tables which start with mdl_feedback....
At the end do a new install with the correct feedback version.