UI Scripting: why this won't work

I found this script on Apple 's site using UI scripting to import
pictures of a folder into iPhoto: this_item is the choosen folder.
//
-- convert the file reference to UNIX style
set this_path to the POSIX path of this_item
-- bring the target application to the front
tell application "iPhoto"
activate
try
tell application "System Events"
tell process "iPhoto"
-- summon the import dialog
click menu item "ImporterŠ" of menu "Fichier" of menu bar
1
-- enter the path to the image in the dialog input

set the value of text field 1 of group 1 of group 2 of
window "Importer des photos" to this_path

delay 1
-- click to start the import
click button "Importer" of window "Importer des photos"
if the last character of (this_item as string) is ":" then
-- it's a folder so click the import button again
click button "Importer" of window "Importer des photos"
end if
end tell
end tell
on error error_message
display dialog error_message buttons {"OK"} default button 1
end try
--
///

I've taken the same code to make a toolbar script , selecting the folder
by:
//
tell application "Finder"
activate
set this_item to (the target of the front window) as string
----
end tell
//

and then when the import window of iphoto opens the line
//set the value of text field 1 of group 1 of group 2 of window
"Importer des photos" to this_path//

returns an invalid path error!!
why?
if you try, make sure you change the names of the menus and buttons
above to english system.

*** remove "_no_junk" for mail replies ***