--- ../gawk-3.1.5-fc4-32/builtin.c	2005-07-26 14:07:43.000000000 -0400
+++ builtin.c	2006-07-07 16:54:42.212660000 -0400
@@ -2462,6 +2462,15 @@ sub_common(NODE *tree, long how_many, in
 	free(t->stptr);
 	t->stptr = buf;
 	t->stlen = textlen;
+#ifdef MBS_SUPPORT
+	if (t->wstptr != NULL) {
+		assert((t->flags & WSTRCUR) != 0);
+		free(t->wstptr);
+	}
+	t->flags &= ~WSTRCUR;
+	t->wstptr = NULL;
+	t->wstlen = 0;
+#endif
 
 	free_temp(s);
 	if (matches > 0 && lhs) {