export bookmarks from safari to firefox

In firefox 3 safari bookmark exporter no longer works when exporting. you can select file>import (the second pull down menu and the 11th item in that menu, there are also two light horizontal gray lines in this menu) and a dialogue box “import wizard”
comes up safari is checked and you can hit return to return to the next box
five checked boxes occur “Preferences, Cookies, Browsing History, Saved Form History, Bookmarks”
I want to uncheck the first 4 and leave the last on checked.
then hit return pause 5 seconds and return again.
I think this is the way to do a menu item but nothing is working.
What am I missing?

tell application "Firefox" to activate
delay 8
try
	tell application "System Events"
		tell process "Firefox"
			set frontmost to true
			click menu item 11 of menu 1 of menu bar item 2 of menu bar 1
		end tell
	end tell
on error e
	display dialog e
end try
tell application "System Events"
	tell process "Firefox"
		
		keystroke return
		
		set pref_val to get value of checkbox "preferences" of window "Import Wizard"
		if pref_val = 1 then
			click checkbox "preferences" of window "Import Wizard"
		end if
		
		set cookie_val to get value of checkbox "cookies" of window "Import Wizard"
		if cookie_val = 1 then
			click checkbox "cookies" of window "Import Wizard"
		end if
		
		set browsing_val to get value of checkbox "Browsing History" of window "Import Wizard"
		if browsing_val = 1 then
			click checkbox "Browsing History" of window "Import Wizard"
		end if
		
		set saved_val to get value of checkbox "Saved Form History" of window "Import Wizard"
		if saved_val = 1 then
			click checkbox "Saved Form History" of window "Import Wizard"
		end if
		
		set Bookmarks_val to get value of checkbox "Bookmarks" of window "Import Wizard"
		if Bookmarks_val = 1 then
		else
			click checkbox "Bookmarks" of window "Import Wizard"
		end if
		keystroke return
		delay 5
		keystroke return
		
	end tell
end tell
end