@ Kovid...Got it to work...finally. I had gotten the same misbegotten error message at PayPal when it dawned on me I probably had their cookies blocked. I unblocked them and the problem was solved (mayhap someone should talk to their programmers about detailed error trapping). Hopefully, you will get it.
I didn't donate much, just what the shareware programs I was looking at would have cost me (I won't buy unless I can try). However, if all 300,000 some odd users of calibre did likewise, you could live off the interest the rest of your life (that was a hint, folks!).
Btw, I added a bit so you can afford that upper case "C" for calibre's name.
@Worldwalker...Thanks. You set off a Ramen craving. Fortunately, I was able to find a package in the cupboard.