Is there any technical reason why an HTML epub book won't work on iPad mini?

Question

im trying to get an epub HTML file that a coworker created to function on the iPad mini with no success, mind you this same file works perfectly fine on an iPad 2 and iPad 3.

We go to the download link, the file apparently downloads from the browser (Safari, I know chrome for ipad has issues with epub) and nothing happens! No open with popup, etc. (Which is exactly what happens with other ipads, open with -> iBooks, book is added).

I don't see anything in particular with the code that I feel could be messing up the installation of said book, however if anyone is feeling adventurous or knows of an issue that could be causing this.. Heres the link to the actual book: www.xtrategia.net/rc/EbookEspIng_Ver_1.epub

Answer 1

Sigil says "Unable to read OPF file. Line: 9 Column 56 - Namespace prefix 'opf' not declared." Sounds like bad XML to me.