Yet another strange thing with Mail.app

Hello!

This script works correctly when I select files from the finder, but not from the Desktop, then I have gotten the files from the last move operation from the Desktop to a folder via Finder.
Can somebody enlighten me a little bit on that?

global selected_items

tell application "Finder"
	activate
	set the selected_items to (selection)
	if the selected_items is {} then
		beep
		display dialog "Please choose some file to attach to a new mail message and run this script again!" buttons {"Cancel"} default button 1
		error number -128
	end if
end tell

tell application "Mail"
	activate
	
	try
		set newMessage to make new outgoing message with properties {visible:true, subject:"My Subject", content:"My Body"}
		
		tell newMessage
			repeat with anAttachment in the selected_items
				tell content to make new attachment with properties {file name:anAttachment as alias} at after the last paragraph
			end repeat
		end tell
	on error the error_message number the error_number
		display dialog "Error: " & the error_number & ". " & the error_message buttons {"Cancel"} default button 1
	end try
end tell

Best Regards

McUsr