This might be of interest to the aMember developers: http://blog.blacknight.com/paypal-users-check-your-code.html Paypal will be changing the way they handle redirects and landing pages.
This won't affect aMember's paypal plugins because in all paypal plugins(v3, v4, standart, pro, express checkout ) aMember redirect users to paypal.com. Localized domain names are not used.