Clean your OpenERP database from remnants of modules, models, columns and tables left by uninstalled modules (prior to 7.0) or a homebrew database upgrade to a new major version of OpenERP.
After installation of this module, go to the Settings menu -> Technical -> Database cleanup. Go through the modules, models, columns and tables entries under this menu (in that order) and find out if there is orphaned data in your database. You can either delete entries by line, or sweep all entries in one big step (if you are really confident).
Caution! This module is potentially harmful and can easily destroy the integrity of your data. Do not use if you are not entirely comfortable with the technical details of the OpenERP data model of all the modules that have ever been installed on your database, and do not purge any module, model, column or table if you do not know exactly what you are doing.