create windows instance dynamicly: create using

Hi

I want to open an object window whose name is stored into a table

this is my code:

//////////////////////////////////////////////////////////////////////

window w_window

integer li_return

string ls_window_name

ls_window_name= 'w_tvdw_tabbas'

w_window = CREATE USING ls_window_name

li_return= open(w_window)

messagebox('li_return',string(li_return))

//////////////////////////////////////////////////////////////////////

This Always return -1

What I am doing wrong ?

Thanks