There is a broken link under the section "Links" | "calibre: Getting Started" | "Getting Help with calibre".
The correct URL is (without the / after help):
http://calibre-ebook.com/help
Thanks for this super informative howto on calibre!
P.S.
Are there any significant differences between this post and the calibre for Beginners guide at:
http://stu.wccnet.edu/~rprice/Eng218/CalibreHelp?