MarkGr has the solution, at least for me. I carefully entered the correct package ID and document ID, hit Continue, and got an error message. With MarkGr's suggestion in mind, though, I just clicked Continue again *without re-entering the package ID and document ID.* I had to do this three times, but then it succeeded and offered me the opportunity to import the data. And away we went. Not a great experience--but waaaaay better than "just enter it manually." Thanks!
