Try to open it in your browser. The error refers to the page length of the pdf, it can't handle the dimensions of the file. Basically the problem is that the walkthroug is on a single page. Sorry for the inconvenience.
I tried opening it in Firefox (after installing Adobe Acrobat add-ons) and all I get is two blank pages. I right click on the file, click on "open" and choose Firefox.
