When I try to install a greasemonkey user script, it displays an alert box with this error: "Could not download user script [Exception..."Cannot modify properties of a WrappedNative" nsresult:"0x80570034 (NS_ERROR_XPC_CANT_MODIFY_PROP_ON_WN)" location: "JS frame :: chrome://greasemonkey/content/greasemonkey.js :: anonymous :: line 251" data: no]" Steps to reproduce: 1. Install Greasemonkey 3.3 and restart Firefox (http://greasemonkey.mozdev.org/) 2. Right-click on of the scripts on that page and select "Install User Script...". Actual Results: The above mentioned error is displayed in an alert box. The download manager shows the download of the script as "Starting...". The js console displays: Warning: assignment to undeclared variable folder Source File: chrome://mozapps/content/downloads/downloads.js Line: 745 Error: doc has no properties Source File: chrome://greasemonkey/content/greasemonkey.js Line: 34 Judging from the error, this is a regression from bug 281988.

I'm using a brand-new Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8b2) Gecko/20050522 Firefox/1.0+.

A few minutes ago I've installed 0.3.3 and it gave me a bunch of problems... Then I've installed 0.3.4 and it worked perfectly. Can you try installing the 0.3.4 version from here and reproducing again ? http://ftp.iasi.roedu.net/mirrors/mozdev.org/greasemonkey/

At least for 0.33 I had to submit the changes from http://mozdev.org/bugs/show_bug.cgi?id=10173 to greasemonkey.js in order to get greasemonkey running.

Greasemonkey 0.3.4 works fine indeed. Looks like this was an error on the extension's side. --> invalid.

In case anyone cares, the extension was setting a nonexistent property on an nsIDownload wrapped native, and this is not allowed for non-DOM wrapped natives (hence the exception).