Prolem with DDD - can't open display

[Ray Hurst]

Hello,
I get the following error message when I type DDD:
Error: Can't open display

Built with the following configuration:
GNU DDD 3.3.9 (i686-pc-cygwin)
Copyright (C) 1995-1999 Technische Universität Braunschweig, Germany.
Copyright (C) 1999-2001 Universität Passau, Germany.
Copyright (C) 2001 Universität des Saarlandes, Germany.
Copyright (C) 2001-2004 Free Software Foundation, Inc.

Compiled with GCC 3.3.1 (cygming special)
Requires X11R6, Xt11R6, Motif 2.1 (GNU/LessTif Version 2.1 Release 0.93.91)
Includes XPM 3.4.11, Athena Panner (7000002L), DDD core
Built 2004-07-15 by U-HUNTHARO <address@hidden>.

Running CygWin DLL version 1.5.25 on windows XP.

Any ideas on what the problem is?