Our issue was resolved. It appeared in our shared Dev Sql Server, someone changed the default RSA_USER's account password. We've create a new account with same permissions and updated this account within the upgrade and it worked. Someone had used the same default script which in turns modifies the same information (database, user, etc.) Fortunately we had created a separate database before hand.
Note to self: Update the SQL scripts that the SSO installation provides with the user accounts "RSA_USER" and "RSA_DBA" to something more like "SSODEVUSER" and "SSODEVDBA".