that is strange. 2 people with same problem and I've never had it happen to me from Pioneer (or any other site for that matter). just for the heck of it I just tried the SC-61 manual off Pio US & it opened & saved just fine.
maybe the firewall angle is an possibility...mine certainly isn't set to block pdf's
if adobe browser plug-in is disabled that would prevent it from opening but saving it to your hard drive by right-clicking on it and save link should still work...