The search string was
It gave me an error page which stateddr heidenhoff's process
And the URI of that page wasAn Error Was Encountered
The URI you submitted has disallowed characters.
That is, it showed the apostrophe correctly, and it also showed spaces direct in the URI bar. So you have an issue of escaping characters rather than correctly substituting URI-appropriate string expansions (like %20 for space) or your own search's version of this.https://librivox.org/search/q/dr heidenhoff's process