Thank you for this malky66.
Yes, the seller just said that he changed his "sales settings" and asked me to try again.
You are therefore right to note that the seller had selected the option allowing the settings to only accept payments from the premium, linked to PayPal accounts, and so on.
However, I think this was a default selection and the seller did not realize that it was potentially restricting its sales by requesting payments only through "premium linked in etc" accounts.
I'm wondering if the paypal sales settings are set by default to request these premium accounts, then the sellers need to change the settings in order to allow payments through a normal account.
It would probably be best to use a normal PayPal process by default, instead of trying to forcibly force the "linked, premium, or business account" to the buyers of the DP content.