Problem with Paypal Express Checkout

Hi there,

I'm working on a site for an client, and running some tests with different payment gateways. Is there someone out there who has set up an Norwegian webshop with MarketPress?

When I set up Paypal in MarketPress Store Settings there is an dropdown to select 'Paypal site', but there is no selection for 'Norway', so I use United States. When I log onto paypal I use .com, so that might be the one to select.. But still, I have validated/checked the settins on the API several times - but still I get the error when selecting PayPal:

"There was a problem connecting to PayPal to setup your purchase. Please try again.
10002 - Security error - Security header is not valid"

Any advise?