I am in the UK which may be why some people get it and some don't, perhaps if you are in the US it works ok?
Further testing seems to show that this only affecting people on UK IP ranges.
Heads up to anyone in the UK who is using the standard PayPal payment interface, this problem is still not fixed and as far as I can tell affects every single UK Business PayPal account (I've tested about 30 that I could find the email addresses for). If you are in the UK and you have PayPal as a payment option please test it for yourself and report back.
PayPal have to date done nothing to fix this.
I've been given a workaround for this problem by a PayPal engineer and this seems to work.
To quote him: "I've got as a workaround (until this gets fixed) is for you to add "Country=gb" or "country.x=gb" to the buttons or links from your website, and that should prevent your customers from seeing this error."
What I've done is add this to my PayPal submit form:
<input type=hidden name=country.x value="GB">
This seems to work for me so perhaps everyone else can try this and report back.