DDE Built-In package - APP_BEGIN function

In the below block of code the dde.app_begin function is attempting to open c:\index_values.xls
I want to use this code but I want to open c:\Documents and Settings\WDG4\Desktop\local\file.xls
But it blows up cause of the space located after the 's' in Documents and the 'd' in and.  I need the exact line of code please for the dde.app_begin line.



DECLARE
      appid pls_integer;
      convid pls_integer;
      x  number;
BEGIN
  appid :=    
    dde.app_begin('c:\program files\microsoft office\office\excel.exe
                                 c:\index_values.xls',dde.app_mode_minimized);

    convid := dde.initiate('EXCEL','c:\index_values.xls');