run the following query against the database to create the Activation Code record
INSERT INTO wa_settings (name, type, options, value, grp, subcategory, cond, description, variable, weight, spry_args, spry_error, help_text)
VALUES ('Activation Code', 'text', '', '<your serial here>', 'Site Settings', NULL, NULL, '', 'PS_Serial', 74, NULL, NULL, NULL);
replace <your serial here> with your serial number.