I didn’t find this problem with my whitespace deletion hack, but if the file you’re editing is less than 25 lines, it bombs out. The (next-line 25) fails and kills the execution of the function.
Here’s the fixed code.
(defun delete-trailing-whitespacep ()
"Should we delete trailing whitespace when saving this file?"
(save-excursion
(goto-char (point-min))
(narrow-to-page)
(goto-char (point-max))
(let ((pos (point)))
(goto-char (point-min))
(re-search-forward (concat "@author +" user-full-name) pos t))
(widen)))