--- a/mercurial/ui.py	Sun Sep 11 18:49:54 2011 +0200
+++ b/mercurial/ui.py	Mon Sep 12 23:02:45 2011 -0500
@@ -667,9 +667,9 @@
         printed.'''
         if self.tracebackflag:
             if exc:
-                traceback.print_exception(exc[0], exc[1], exc[2])
+                traceback.print_exception(exc[0], exc[1], exc[2], file=self.ferr)
             else:
-                traceback.print_exc()
+                traceback.print_exc(file=self.ferr)
         return self.tracebackflag
 
     def geteditor(self):