[Sage] Sage install error under FF 2.0.07/Linux

[Mark Petrovic]

I'm having difficulty installing Sage in Firefox v2.0.0.7 under Linux.
 When I click on the install link
https://addons.mozilla.org/en-US/firefox/downloads/file/378/sage-1.3.10-fx.xpi,
the install dialogue starts, presents me with the Install button after
a few moments, then terminates with an error dialogue (where OK is the
only option):

Firefox could not install the file at

http://releases.mozilla.org/pub/mozilla.org/addons/77/sage-1.3.10-fx.xpi

because:  Download error
-228

Any ideas on what might be going wrong and how to fix it?

Thanks.

-- 
Mark