Comment 2 for bug 65609

User-Agent: Mozilla/5.0 (compatible; Konqueror/3.5; Linux) KHTML/3.5.5 (like Gecko) (Kubuntu)
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; de; rv:1.8.1) Gecko/20060601 BonEcho/2.0 (Ubuntu-edgy)

I'm experiencing an "unknown error -203" during installation or update of extensions in firefox 1.99+2.0rc2+dfsg-0ubuntu1.
The error seems to prevent installing new extensions, while despite the error updating existing extensions seems to work (at least they don't show up after a restart as updateable anymore).
The error console shows:
 """
 installLocation has no properties
 file:///usr/lib/firefox/components/nsExtensionManager.js line: 3849.
 """
This is also present in the RC2 release.

It's basically the same issue as bug 352847, but I could not re-open nor leave a comment there.

Also, I'm not sure if the simple patch fixes the root of the problem.

Reproducible: Always

Steps to Reproduce:
1. Install or update an existing extension

Actual Results:
 installLocation has no properties
 file:///usr/lib/firefox/components/nsExtensionManager.js line: 3849.
in error console