The error is objecting to the Currency code that you have set in the si_preferences file. You can look in the database si_preferences table and near the end of each record, see what you have in the currency_code field. They should all be alpha values and each 3-characters long. This link, IBAN Currency Codes shows the list of valid codes for each country. Make sure all the currency_code values in the si_preferences table have valid alpha codes from this table.