I'd just like to know something: it appears that this gadget overrides or replaces the default Windows calendar gadget, and seems to use the same code. Is it possible to get the original Windows calendar gadget back, or to have the two calendars co-exist independently, so that I can switch freely between them? Thanks.
I had the same problem, but when I put it in my regular Program Files>Windows Sidebar>Gadgets folder instead of my Program Files (x86)>Windows Sidebar>Gadgets folder, I was able to see it when I clicked right clicked on the sidebar and clicked, "Add Gadgets". I just installed it from there. Maybe that will work for you, I hope.