Ajax, is this the look of the webpage you're seeing?
When I test, I'm taken to PayPal and asked to either log in with a PayPal account, or the second option is to pay as a "guest" where you can enter credit card info as a one time payment.
This is the area that may ask for your country, among other things. For me, "United States" is chosen by default, but I'm able to change it, as you can see from this screen shot above.
It should work fine, as I've been receiving new membership payments and no complaints. Maybe something related to your browser is blocking the options? Or PayPal was having a hiccup at the moment you tried? Not sure.
The best suggestion I have at the moment is to try again later, and if the issue persists, try from another web browser, or even another computer if you have access.