Vista Gadget deploying problem

You have created a Vista Sidebar Gadget, but when you try to install the gadget on your system nothing happens and in your directory(C:\Users\UserName\AppData\Local\Microsoft\Windows Sidebar\Gadgets) there's a folder named : mygadget.gadget.~0000

2 possible problems :

- The Zip package: don't zip your gadget root folder directly, instead go inside it and zip up all its contents (files and folders) with right-click / Sent To / Compressed (zipped) Folder.

- Special chars in manifest file: you must encode special chars like accents in gadget.xml.

Sample chars to replace:
é by é
è by è
, (comma) by ,
! by !
? by ?
@ by @

You can find a good list of special chars codes there :
http://resources.bravenet.com/quickref/special_chars