Actually, my error, or my browser’s error. The first time I followed your link, it didn’t take me to the comment.
I would agree with Dr. McGrath that Jesus did predict the end during his lifetime. I think that the early church expected the end during their generation, but they came to a new understanding before the end of the apostolic age and started to deal with the “soon” issue.
Since I don’t see prophecy as prediction, I’m not sure I would use the word “mistake,” though it is an unfulfilled expectation. For example, if my business projections are off for a month, that doesn’t keep me from making further sales projections.
Perhaps I’m being too picky here, however, in distinguishing a hope regarding something one can’t know, versus a real prediction that fails. Bible prophecy (and its interpretation) is filled with unfulfilled expectations!
I wrote some notes on a book that deals with this, The Adventists’ Dilemma. In that book, Dr. Edward W. H. Vick takes aim at his own denomination (Seventh-day Adventist) and their constant use of “soon,” which he believes is either wrong (if you mean soon in the normal sense) or meaningless (if you create a special sense.