OK - sorry for the delay, Christmas and all that.
The reason you are getting this error is because the table you are trying to edit has no primary key. Edit Any table uses the primary key to identify which record it is going to update, this is the only way it can uniquely identify the record. If you have access to something like PhpMyAdmin you can add an auto incrementing primary key to the table. I have tested this and the Contact Form 7 DB plugin still works fine and Edit Any Table is then able to do it's stuff. HTH