Running Application in Background

Hi,
I would like to run the following script but I cannot get it to run in the background. I can hide it once by calling “system preferences” but because it repeats and recalls Quicktime. Thank you for your help.


tell application "Finder" to set sorted_items ¬
	to files of folder HFSpath whose name ends with ".mp4"
repeat with i from 1 to the count of sorted_items
	set this_item to (item i of sorted_items)
	tell application "QuickTime Player"
		if i is equal to 1 then
			make new document
		end if
		open this_item
		tell document 1
			rewind
			select all
			copy
			select none
		end tell
		close document 1 saving no
		tell document 1
			add
			select none
		end tell
	end tell
end repeat

tell application "QuickTime Player"
	if exists window 2 then
		close window 2
	end if
	set filename to (path to desktop folder as string) & legalName & "1" & ".mov"
	set newfilename to (path to desktop folder as string) & legalName & ".mov"
	set dimensions of document 1 to {320, 180}
	resize document 1 by 100
	save self contained document 1 in newfilename
	close window 1
	quit
end tell