Error in Moodle when trying to move activity to other course

We have a Moodle site running Moodle 2.2.3. Recently we had a new error show up when trying to import activities from one course to another: error/error_question_answers_missing_in_db The error is confusing since I tried importing without a quiz and still got a similar error. I also tried the backup/restore method of moving activities and got the same error. We need to fix this so that we can move activities from one course to another. We recently installed two new custom activities and those might be causing the error, the import was working before those were installed. That was a few months ago though, so it may not be related to the activities at all. I need someone who has worked with Moodle before, this is a complex live site and we need to work carefully to not affect the users who are currently using it. We will need some time at the beginning of the project for me to help you get access to the site and review the problem. Please let me know if you have any questions about the project before placing a bid.