Index: trunk/src/org/openstreetmap/josm/gui/layer/gpx/DownloadAlongTrackAction.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/layer/gpx/DownloadAlongTrackAction.java	(revision 9816)
+++ trunk/src/org/openstreetmap/josm/gui/layer/gpx/DownloadAlongTrackAction.java	(revision 9817)
@@ -81,4 +81,7 @@
                 latcnt++;
             }
+        }
+        if (latcnt == 0) {
+            return null;
         }
         double avglat = latsum / latcnt;
@@ -190,5 +193,8 @@
     @Override
     public void actionPerformed(ActionEvent e) {
-        Main.worker.submit(createTask());
+        PleaseWaitRunnable task = createTask();
+        if (task != null) {
+            Main.worker.submit(task);
+        }
     }
 }