hello,
I will publish an update with the Norwegian currency asap. It was just recently added by Paypal, we didn't catch up.

If you need it urgent, please edit this file:
core/base/code/core/appSettings.php

on line 76 add this line:

'Norwegian Krone'    => 'nok',

So finally that part of code will look like this:

$currOptions = array(
    'USD U.S. Dollar'        => 'usd',
    'EUR Euro'                => 'eur',
    'GBP Pound Sterling'    => 'gbp',
    'AUD Australian Dollar'    => 'aud',
    'CAD Canadian Dollar'    => 'cad',
    'JPY Japanese Yen'        => 'jpy',
    'Norwegian Krone'        => 'nok',
    );