Error 42: Symbol Undefined...

[doob]

I'm new to D and DWT (but not SWT) and I'm trying to do this simple thing:

import dwt.all;

void main ()
{
	Display display = Display.getDefault();
}

and I get this output:

C:\>dmd -d main.d
link main,,,user32+kernel32/noi;
OPTLINK (R) for Win32  Release 7.50B1
Copyright (C) Digital Mars 1989 - 2001  All Rights Reserved

main.obj(main)
 Error 42: Symbol Undefined _D3dwt7widgets7display7Display10getDefaultFZC3dwt7wi
dgets7display7Display
--- errorlevel 1

What I'm I doing wrong?
(excuse for any bad English)