Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/PlLinesToWaternetConverter.cs
===================================================================
diff -u -r5276 -r5284
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/PlLinesToWaternetConverter.cs	(.../PlLinesToWaternetConverter.cs)	(revision 5276)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/PlLinesToWaternetConverter.cs	(.../PlLinesToWaternetConverter.cs)	(revision 5284)
@@ -582,6 +582,10 @@
         for (var i = 0; i < xCoordinates.Length - 1; i++)
         {
             List<Line> relevantLinesAtX = splitLines.FindAll(line => Math.Abs(line.BeginPoint.X - xCoordinates[i]) < toleranceAlmostEqual && Math.Abs(line.BeginPoint.X - line.EndPoint.X) > 0);
+            if (relevantLinesAtX.Count == 0)
+            {
+                continue;
+            }
             double minZBegin = relevantLinesAtX.Select(line => line.BeginPoint.Z).Min();
             List<Line> relevantLinesAtXWithZBeginMax = relevantLinesAtX.FindAll(line => Math.Abs(line.BeginPoint.Z - minZBegin) < toleranceAlmostEqual);
             double minZEnd = relevantLinesAtXWithZBeginMax.Select(line => line.EndPoint.Z).Min();