Index: /applications/editors/josm/plugins/walkingpapers/src/org/openstreetmap/josm/plugins/walkingpapers/WalkingPapersLayer.java
===================================================================
--- /applications/editors/josm/plugins/walkingpapers/src/org/openstreetmap/josm/plugins/walkingpapers/WalkingPapersLayer.java	(revision 18471)
+++ /applications/editors/josm/plugins/walkingpapers/src/org/openstreetmap/josm/plugins/walkingpapers/WalkingPapersLayer.java	(revision 18472)
@@ -207,4 +207,10 @@
 		g = bufferImage.getGraphics();
 
+        if (!LatLon.isValidLat(topLeft.lat())  ||
+            !LatLon.isValidLat(botRight.lat()) ||
+            !LatLon.isValidLon(topLeft.lon())  ||
+            !LatLon.isValidLon(botRight.lon()))
+            return;
+
 		viewportMinX = lonToTileX(topLeft.lon());
 		viewportMaxX = lonToTileX(botRight.lon());
@@ -366,4 +372,6 @@
 	@Override
 	public void visitBoundingBox(BoundingXYVisitor v) {
+        if (printBounds != null)
+            v.visit(printBounds);
 	}