auto update fails :(

Hello all,

So I have an extension that I want to be able to update using an
update.rdf file.  First I made an rdf by looking through sample rdfs,
but when I treid to use it firefox gave me this error:

"Firefox could not check for updates for the following components
(either the update server(s) did not respond or the update service(s)
were not found)"



So then I thought... well I probably put the file together wrong after
all, so I poked around some more and I found this site

http://www.gmacker.com/web/content/tutorial/firefox/updatefirefoxext.htm

which actualy generates a update.rdf for you.  So I tried that and
lo-and-behold, I get exactly the same error...

I have my .xpi in the right place... I'm at a loss cause I don't know
what's going wrong :(


Any ideas?