491005 - AppleScript error: Can't get <<class curl>> of window 1

Status: RESOLVED DUPLICATE of bug 516502

(Firefox :: General, defect)

Description

[Hide Kay]

User-Agent:       Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.5; en-US; rv:1.9.1b5pre) Gecko/20090501 Shiretoko/3.5b5pre
Build Identifier: Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.5; en-US; rv:1.9.2a1pre) Gecko/20090429 Minefield/3.6a1pre ID:20090429030951

This AppleScript passes the current tab's URL to other web browsers.

tell application "Minefield"
	set theURL to «class curl» of window 1
end tell
tell application "Safari"
	activate
	open location theURL
end tell

When running this script from the AppleScript menu on the menu bar, the script does not work. When clicking on the script file directly, the following warning appears:
"AppleScript Error Minefield got an error. Can't get <<class curl>> of window 1"

The problem occurred only with Minefield 3.6a1pre. Shiretoko and Firefox 3.0.x work fine.

Reproducible: Always

Steps to Reproduce:
1.Display any web page with Minefield
2.Run script
3.
Actual Results:  
Nothing happens.

Expected Results:  
The script should send the URL to other browsers.

Is this script error the same as Bug #490830?