Index: trunk/src/libgrbs/route_next.c
===================================================================
--- trunk/src/libgrbs/route_next.c	(revision 1327)
+++ trunk/src/libgrbs/route_next.c	(revision 1328)
@@ -338,7 +338,7 @@
 	grbs_arc_t *arc;
 
 	arc = from->link_2net.next;
-	if ((arc->parent_pt == to_pt) && (arc->concave == to_is_concave)) {
+	if ((arc != NULL) && (arc->parent_pt == to_pt) && (arc->concave == to_is_concave)) {
 		*from_ang = from->sa + from->da;
 		*to_ang = arc->sa;
 		return arc;
@@ -345,7 +345,7 @@
 	}
 
 	arc = from->link_2net.prev;
-	if ((arc->parent_pt == to_pt) && (arc->concave == to_is_concave)) {
+	if ((arc != NULL) && (arc->parent_pt == to_pt) && (arc->concave == to_is_concave)) {
 		*from_ang = from->sa;
 		*to_ang = arc->sa + arc->da;
 		return arc;