This error message 10565 The merchant country is not supported usually appears when someone is using Paypal Pro outside of the allowed countries. For now, it is only available for use it in the UK, USA and Canada. Here's more on this:

If you want to use PayPal's service but are domiciled outside the UK, USA and Canada, check out PayPal's other options: PayPal Payflow Pro, PayPal Standard and PayPal Express Checkout.