**your PayPal account may be set to require manual approval of payments, after which they would notify us of payment completion so we could log the transaction and issue any download links. **
It was set to require manual approval of payments.
It is not necessary to have any IPN set in your PayPal account if you are using purchase button codes provided by E-junkie.
Not so, at least not in this case. Not trying to be contrary, but the truth is I was (and am) using button codes provided by E-junkie, and as I said, I still had to reset the I P N settings manually at Paypal, since it was off. So apparently future users, aberrations can happen.
But again, all seems to be working fine now. Thank you very much for your help!