Problem with downloading signed script components in a Firefox extension

[Andrew Groom]

Hi All,

I have a FF extension that's downloading some script modules from our
server at run time via dojotoolkit, which is essentially just using
xmlhttp. For increased security, I'm packaging the script in a signed
jar and referencing items within it with the syntax, e.g.:

jar:http://somewhere.com/modules/modules.jar!/somescript.js

The retrieval of these components works fine in FF 1.5 and 2.0 on Linux
and Windows 2000 but just fails silently in all Firefoxes on Windows XP,
which (unfortunately) a few of my users are using :-)

The same extension is happily interacting with the server to retrieve
other static content, post requests, etc., so it seems to be something
specific to the signed jar approach.

Any ideas ? It's pretty critical to get this fixed soon, so any help
greatly appreciated.

Cheers, Andrew.