Backtrace on start

[mcepl]

I just copied esv.el to ~/.emacs.d, added the suggested snippet to ~/.emacs (does anything bad happens to me when I edit ~/.emacs with vim? ;)), started Emacs and run <Ctrl-C>e. Then I have asked for J 3:16. The result in a separate window is:

Debugger entered--Lisp error: (error "XML: (Not Well-Formed) Only one root tag allowed")
  signal(error ("XML: (Not Well-Formed) Only one root tag allowed"))
  error("XML: (Not Well-Formed) Only one root tag allowed")
  xml--parse-buffer(nil nil)
  xml-parse-region(1 512)
  (progn (insert xml) (xml-parse-region (point-min) (point-max)))
  (unwind-protect (progn (insert xml) (xml-parse-region (point-min) (point-max))) (and (buffer-name temp-buffer) (kill-buffer temp-buffer)))
  (save-current-buffer (set-buffer temp-buffer) (unwind-protect (progn (insert xml) (xml-parse-region (point-min) (point-max))) (and (buffer-name temp-buffer) (kill-buffer temp-buffer))))
  (let ((temp-buffer (generate-new-buffer " *temp*"))) (save-current-buffer (set-buffer temp-buffer) (unwind-protect (progn (insert xml) (xml-parse-region (point-min) (point-max))) (and (buffer-name temp-buffer) (kill-buffer temp-buffer)))))
  esv-xml-to-list("<br />\n<b>Warning</b>:  Invalid argument supplied for foreach() in <b>/var/www/esvapi.org/esv/share/common/crossway.xml.1.0.php</b> on line <b>95</b><br />\n<!DOCTYPE crossway-bible SYSTEM \"http://www.gnpcb.org/esv/share/schemas/crossway.base.entities.dtd\">\n<crossway-bible class=\"passage-query\">\n<copyright>The Holy Bible, English Standard Version copyright (c)2001 by Crossway Bibles, a division of Good News Publishers. Used by permission. All rights reserved. http://www.esv.org</copyright>\n</crossway-bible>")
  (esv-walk-tree (esv-xml-to-list (esv-get-query (list (list (quote passage-query) reference)))))
  (insert (esv-walk-tree (esv-xml-to-list (esv-get-query (list (list (quote passage-query) reference))))))
  esv-passage("J 3:16")
  call-interactively(esv-passage nil nil)

What's wrong with me?

[mcepl]

OK, so it was just a bad reference (Jn 3:16 works just fine), but some a little bit more gracious error handling would be lovely.