diff -wur mrbayes-3.1.2.orig/sump.c mrbayes-3.1.2/sump.c
--- mrbayes-3.1.2.orig/sump.c	2005-12-24 05:26:29.000000000 +1300
+++ mrbayes-3.1.2/sump.c	2007-08-02 10:40:30.000000000 +1200
@@ -943,6 +943,16 @@
 		i = 0;
 		if (FindValidCommand (sumpToken, &i) == ERROR)
 			MrBayesPrint ("%s   Could not find sump\n", spacer);
+	
+#	if defined (MPI_ENABLED)
+		ierror = MPI_Barrier (MPI_COMM_WORLD);
+		if (ierror != MPI_SUCCESS)
+			{
+			MrBayesPrint ("%s   Problem at chain barrier\n", spacer);
+			/* We are already returning an error anyway */
+			}
+#	endif
+
 		return (ERROR);	
 	
 }