Add to Party Shuffle

Hi,

I'm trying to write a script that given a file adds it in Party
Shuffle (in iTunes).

It looks like this

on open argv
	tell application "iTunes"
		set theParty to some playlist whose special kind is Party Shuffle
		repeat with thisFile in argv
			add thisFile to thePosition of theParty
		end repeat
	end tell
end open

Unfortunately it doesn't work... I'm pretty sure it did work before,
but no more. I get the error message: "Item 1 {alias "filename.mp3"}
doesn't understand the  =ABevent hookAdd=BB message." Soo, what does that
mean? I have no idea, do you?

- M=E5rten