package gadget valid a not is This / Problem Gadgets
I programmed a gadget and had this problem. While you'll try to download it you'll get following in IE "This is not a valid gadget package".
Why it's ZIP???
First time i don't know what the Problem is. I just thought my gadget has a problem.
While you'll try to download it you see .ZIP extention just because .Gadget is really .ZIP, so "smart" IE knows to "translate" extention in order to prevent fraud. Very nice, but I want do download and install gadget.
After some deep searching I found it.
It was an IIS 7 Configuration Problem:
The right MIME type for Vista SideBar Gadget is application/x-windows-gadget. Register .gadget extention with application/x-windows-gadget MIME type and you'll able to provide your visitors like installation option for gadgets.