Unfortunately, deleting the database references puts the hack in an unknown state so you may have multiple instances where you will need to follow the suggestion provided until the uninstall completes successfully. You may have some other residue that pops up as well. Hope it works out for you. If all else fails you might want to consider the alternative which is to reinstall the hack in upgrade / overwrite mode then do the uninstall. That should clean up any residual stuff that might be hiding out on your system.