Error adding partner function

I am a newbie. I am trying to configure SD on my IDES.

I am at the point of adding partner function (Z9) to the partner procedure (ZAG)

but I am getting an error message:

"Partner function Z9 cannot be used for partner procedures"

I cannot find the answer in google. please help.

[click for image|http://i1181.photobucket.com/albums/x421/darkmatter1/196235/pfunction.jpg]