File talk:NIR 3VT.oxt

I wanted to create a templates extension, containing .ott files within subfolders. I downloaded the "empty extension" provided, changed the .oxt file extension to .zip file extension, unzipped it, put my subfolders containing the .ott files, then created the .zip archive, then finally changed the .zip file extension to .oxt file extension. But when I tried to install the .oxt file in OpenOffice.org 2.4 something went wrong: the Extension Manager lists the new extension but does not mark it as "Abilitato" (I'm using the italian version of OOo 2.4, under Windows XP Pro SP2, JRE 6u5) and the templates, of course, do not show (in the Extension Manager list, under the new extension, the "Paths.xcu" indication is missing). I tried to install the extension on another PC, but the same problem occurred again. What am I missing? (I upload the extension as I created it: NIR_3VT.oxt) Thanks in advance for any kind help.