diff --git a/debug.py b/debug.py
index 6b90624..3a27b03 100644
--- a/debug.py
+++ b/debug.py
@@ -5,6 +5,7 @@ __version__ = '$Change$'
 # $Id$
 
 from twisted.internet import reactor
+import twisted.internet.error
 
 # Make sure to update the global line when adding a new function
 __all__ = [ 'appendnamespace', 'insertnamespace', 'insertringbuf' ]
@@ -67,4 +68,7 @@ def doDebugging(opt):
 		
 	sf = telnet.ShellFactory()
 	sf.protocol = Debug
-	reactor.listenTCP(56283, sf)
+	try:
+		reactor.listenTCP(56283, sf)
+	except twisted.internet.error.CannotListenError:
+		print 'WARNING: cannot bind to debugger port.'