I can confirm that the document does not display in
Okular (it's what I use on my Slackware 64-bit machines). Won't work in
xpdf either.
Do you actually have
Adobe Reader installed and working (on a 32-bit box or in MultiLib on a 64-bit box)?
If you
do have a working
Adobe Reader it is possible -- possible! -- that the web site is blocking non-
Windows or
Mac servers by looking at your browser's
User Agent (and not seeing
Windows or
Mac in it). Naughty of them, but there you are. You can see what you're reporting to web sites with
http://whatsmyuseragent.com/.
It is also possible that the document specifically looks to see if your PDF reader is
Acrobat Reader and, if not, it will refuse to open the forms; if you're not using
Acrobat Reader, well, that message is all you're going to see.
Anyway, you can try updating to the most current
Adobe Reader (but not on a 64-bit box without MultiLib) and see what's what (or simply use your Windows or Mac and put a hex on the buggers for doing this).