DDE Connection

Hi there.
I am able to communicate with the applicaton (shell) via two simple function calls :

AppActivate "MyApp"
SendKeys "{ESC}" & "command"

that happends from a standalone VB exe Project. I would really want to use DDE communication with calls :

ch = DDEInitiate("XXX", "XX")
'Sends commands on the first screen.
Call DDEExecute(XX, "<commands>")
Call DDETerminate(XX)

but for some reason the DDEInitiate call does not compile at all :
Error : Sub or Function not defined. On the contrary, I could call the DDExxx functions from my VBA macro projects (not standalone VB) but I really need a VB exe proj to do that.

i am wondering if I have to include a module (DDE) to project references or anything?

Appreciate your help. Thank you.