Sounds like whatever you used to DeDRM it did something wonkily suspicious to the book.
Best way to DeDRM your books -- use the tools from
http://apprenticealf.wordpress.com -- those definitely work as expected. Bonus -- it installs in calibre, and you don't have to use a separate app.
P.S. Please remove the book, as it is copyrighted material -- which makes posting it here copyright infringement.