Index: DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Importer/CsvImporterCharacteristicPoints.cs
===================================================================
diff -u -r3148 -r3176
--- DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Importer/CsvImporterCharacteristicPoints.cs	(.../CsvImporterCharacteristicPoints.cs)	(revision 3148)
+++ DamTools/LayerOnSlopeTool/trunk/src/Deltares.LayerOnSlopeTool.Importer/CsvImporterCharacteristicPoints.cs	(.../CsvImporterCharacteristicPoints.cs)	(revision 3176)
@@ -35,8 +35,8 @@
     /// </summary>
     public class CsvImporterCharacteristicPoints
     {
-        private List<CharacteristicPointsRecord> characteristicPointsRecords = new List<CharacteristicPointsRecord>();
-        private List<string> errorMessages = new List<string>();
+        private readonly List<CharacteristicPointsRecord> characteristicPointsRecords = new List<CharacteristicPointsRecord>();
+        private readonly List<string> errorMessages = new List<string>();
 
         public class CharPoint
         {
@@ -65,7 +65,7 @@
             if (index < 0)
             {
                 var csvHeaderFieldError = "The header misses the field: ";
-                throw new ArgumentException(string.Format("{0} : {1} {2}", fileName, csvHeaderFieldError, fieldName));
+                throw new ArgumentException(string.Format("{0} : {1} {2} at index {3}.", fileName, csvHeaderFieldError, fieldName, index));
             }
         }
 
@@ -504,7 +504,6 @@
         public List<string> ErrorMessages
         {
             get { return errorMessages; }
-            set { errorMessages = value; }
         }
 
     }