After endless fun (not!) trying to install it, I eventually found it wouldn't do it in Chrome, but would in IE 9, so did it that way.
That was not the end of the matter, however, as now it's installed, it won't work. Every time I try to download a programme, it tries to force a re-install, even though it's already installed.
FAQs indicate this is a known - and recent - problem with Chrome, and that the workaround is to use another browser.
So back to IE again...
Except I'm having exactly the same problem. It won't download there either, and is trying to force a new install of the (just installed) software.