Another update: I can confirm that the problem still exists for German PayPal / Evernote users in September 2014.
I wonder who will arrange the 5-year anniversary of this open problem? I am currently moving to a bigger place, so we could meet in Bavaria, 30 miles from Munich. Munich - the Oktoberfest city, and Oktoberfest starts in eight days. So, if anyone feels like joining the anniversary in Bavaria...
My situation is as for several other users in this thread: I use PayPal a lot for single payments AND for recurring payments where the recipient is located in the USA. In other words, this is NOT a general problem of PayPal not being able to process this kind of requests.
I called PayPal support, and they told me: Yes, they see that I made a payment request to Evernote.com three times within the last half hour, and that PayPal each time tried to approve the payment, but that this did not work. Why, they cannot say from their logs: could be browser cookies, could be the recipient's use of the API, could be that something within PayPal does not work right. It is not browser cookies; after testing with the same results on IE and Chrome, and after clearing cookies, it still does not work.
After trying to use GER_TX's workaround from one message above this one, contacting email@example.com, asking for a gift option, I must say that it is unuusally difficult to send money to Evernote - this email account does not exist any more. Guess what Evernote Help tells me about gifting? "Evernote Premium customers can purchase 1 gift per month - Both free and Premium customers can also contact firstname.lastname@example.org to apply for a one-time exception to the purchase limit." Interesting, to say the least.
OK, the official way to contact Evernote support nowadays is through the "Contact support" menu point in Evernote. Trying that now.