Index: DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.LayerCreator/SurfacelineProcessor.cs
===================================================================
diff -u -r3192 -r3215
--- DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.LayerCreator/SurfacelineProcessor.cs	(.../SurfacelineProcessor.cs)	(revision 3192)
+++ DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.LayerCreator/SurfacelineProcessor.cs	(.../SurfacelineProcessor.cs)	(revision 3215)
@@ -39,8 +39,15 @@
         {
             surfaceLine = orgSurfaceLine;
             dikeTopPolder = surfaceLine.GetSurfaceLinePointByType(CharacteristicPointType.DikeTopAtPolder);
+            if (dikeTopPolder == null)
+            {
+                throw new Exception(string.Format("Surface line {0} has no Dike Top.", surfaceLine.SurfaceLineId));
+            }
             dikeToePolder = surfaceLine.GetSurfaceLinePointByType(CharacteristicPointType.DikeToeAtPolder);
-
+            if (dikeToePolder == null)
+            {
+                throw new Exception(string.Format("Surface line {0} has no Dike Toe.", surfaceLine.SurfaceLineId));
+            }
         }
 
         /// <summary>Creates the lowered surface line.</summary>
@@ -68,6 +75,7 @@
                     }
                 }
             }
+            loweredSurfaceLine.SurfaceLineId = surfaceLine.SurfaceLineId + "_low";
             return loweredSurfaceLine;
         }
 
Index: DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.LayerCreator/LayerCreator.cs
===================================================================
diff -u -r3214 -r3215
--- DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.LayerCreator/LayerCreator.cs	(.../LayerCreator.cs)	(revision 3214)
+++ DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.LayerCreator/LayerCreator.cs	(.../LayerCreator.cs)	(revision 3215)
@@ -101,10 +101,9 @@
                 loggedLocations.Add(string.Format("Handling location {0} with surface line {1}", location.LocationId, location.SurfacelineId));
                 WriteToLog(loggedLocations);
                 SurfaceLine surfaceLine = FindSurfaceLine(location.SurfacelineId);
-                var loweredSurfaceLine = DetermineSurfaceLineForGivenLayerData(surfaceLine, location.LayerThickness);
-
                 try
                 {
+                    var loweredSurfaceLine = DetermineSurfaceLineForGivenLayerData(surfaceLine, location.LayerThickness);
                     CreateGeometryWithLoweredSurfaceLine(loweredSurfaceLine, location);
                     CreateGeometryWithOriginalSurfaceLine(surfaceLine, location);
                 }