Quark Express 2016 object reference of text style range

Quark 2016
OSX 10.10

I’ve upgraded from quark 10.5 to quark 2016 and I have an old applescript that no longer works.

In this case it is a script to find the location of any text in a text box which has been made Italic.


tell application "QuarkXPress 2016"
	activate
		tell document 1
		
		set selectboxes to object reference of every text box whose selected is true
		
		set thebox to item 1 of selectboxes
		
		set obrefs to object reference of every text style range of story 1 of thebox whose style is {italic}
		
	end tell
end tell

I am getting the error message:
error “QuarkXPress 2016 got an error: Can’t make some data into the expected type.” number -1700 to item on the obrefs line.

I am guessing that something has changed since 10.5 but can;t for the life of me work out what! Any help appreciated.