Every time i Google i get the Chrome browser - grr! But I'm trying to understand this:
use another mechanism via the chrome module. See OS.File and/or the MDN File I/O snippets.
Where can i find documentation for this Firefox+Javascript module? How to Append to a file in a Firefox add-on?
Updated my answer in that other question. I was talking about the SDK chrome module, which is just a way to access Components and with that the XPCOM services and components, so basically what every "old school" XUL add-on gets.