Can't join shared photo stream
I have Windows 7 and I got an e-mail with a link to join a shared photo stream.
I've asked the person if he can just e-mail me the pictures, but he says he doesn't know how, so it looks like I have to deal with all this stuff. So...
I created an apple ID. I installed iCloud Control Panel 2.1. I checked the box in iCloud CP next to Photo Stream (and also both boxes in the Photo Stream options). I signed in to iCloud with my Apple ID. I've closed things and restarted my computer and tried eveything else I can think of, but still when I click on the "Join this Photo Stream" link in the e-mail I just get taken to the page that tells me how to set things up.
So what am I doing wrong? Do I need to have iTunes or some specific photo viewer installed or something too? I don't see anywhere that it says I do, but I can't get it working the way it is.
Windows 7