How do you install an iTunes Visualizer in Windows 7?

Question

How do you install any visualizer other than the default visualizer that ships with iTunes 10 in Windows 7. I've tried placing qtz files in my C:\Users\<username>\AppData\Roaming\Apple Computer\iTunes\iTunes Plug-ins folder and restarting iTunes, but of course no other visualizers can be selected.

Common visualizers that I would like to install include those found here

I'm of course aware that some of these are Mac OS only due to library dependencies - I would still like to know if it's possible to install any visualizer other than the default for iTunes in Windows 7

Solution

I suggest downloading one from here which is compatible with windows and see if you get the same error. You'll notice the ones which are compatible with windows have the correct extension.