[Project_owners] a little problem with install

[Jesper Staun Hansen]

hello

When I press my XPI INSTALL LINK on http://heroes.mozdev.org/ then 
normally firefox shows the installation dialog for xpi addons, but now 
it just shows the dialog for download.
The HTTP header is this:

HTTP/1.x 200 OK
Date: Fri, 25 Jan 2008 12:32:51 GMT
Server: Apache
Vary: Host
X-Powered-By: PHP/4.4.7
content-disposition: attachment; filename="heroes-0.5.5.2-1.xpi"
Content-Length: 84394
Last-Modified: Fri, 25 Jan 2008 12:31:04 GMT
Keep-Alive: timeout=2, max=100
Connection: Keep-Alive
Content-Type: application/x-xpinstall


Other projects on the site doesnt behave like this. On a sidenote:
This works: http://downloads.mozdev.org/heroes/heroes-0.5.5.2.xpi
This one doesn't: http://downloads.mozdev.org/heroes/heroes-0.5.5.2-1.xpi

Doesnt it work anymore when using this linking?