Index: trunk/src/org/openstreetmap/josm/actions/mapmode/ImproveWayAccuracyHelper.java
===================================================================
--- trunk/src/org/openstreetmap/josm/actions/mapmode/ImproveWayAccuracyHelper.java	(revision 8589)
+++ trunk/src/org/openstreetmap/josm/actions/mapmode/ImproveWayAccuracyHelper.java	(revision 8590)
@@ -86,4 +86,10 @@
         for (Node n : w.getNodes()) {
             EastNorth nEN = n.getEastNorth();
+
+            if (nEN == null) {
+                // Might happen if lat/lon for that point are not known.
+                continue;
+            }
+
             currentDistance = pEN.distance(nEN);