It seems like you ran in the same error which occured to me - check if you can access the database with SUPERDBA, if it's not possible set the password again with
db_execute ALTER PASSWORD SUPERDBA <password>
See http://service.sap.com/sap/support/notes/1882932 (Upgrade 7.9.07 BUILD 014-123-244-287 to 7.9.08.22 not possible).