[Asiaplay]

It will not be 2nd language based error (as currency symbol and exchange rate is not defined in language packs).

This alternative currency should be set in X-Cart Admin -> General Settings -> General Options using box next to "Alternative currency symbol (empty to disable). Note that credit card charges are made using primary currency: " (is stored in a config settings SQL table from memory).

At a guess it appears maybe your "alternative currency" exchange rate is not set in your store - so perhaps check X-Cart Admin -> General Settings -> General Options (and make sure that you do not have zero in "Alternative currency exchange rate: " and that it is a decimal e.g. 1.34 - do not use a comma)

Hope helps - cheers, Asiaplay