Index Out OF Range Exception

It's strange few days ago everything was running fine now i getting 2 IndexOutOFRange Exception errors. Does anyone have any ideas how to fix this ....

using UnityEngine; using System.Collections; using UnityEditor;

[CustomEditor(typeof(SpawningMachyne))] public class SpawnEditor : Editor { public override void OnInspectorGUI() { SpawningMachyne SM = target as SpawningMachyne;

     EditorGUI.BeginChangeCheck();

     EditorGUILayout.PropertyField(serializedObject.FindProperty("m_Script"));
     SerializedProperty ob = serializedObject.FindProperty("holder");
     EditorGUILayout.PropertyField(ob);
     if(ob.isExpanded)
     {
         EditorGUI.indentLevel += 1;

         EditorGUILayout.PropertyField(ob.FindPropertyRelative("Array.size"));

         for (int i=0; i < ob.arraySize; i++ )
         {
             SerializedProperty el = ob.GetArrayElementAtIndex(i);
             EditorGUILayout.PropertyField(el);

             if (el.isExpanded)
             {
                 EditorGUI.indentLevel += 1;

                 EditorGUILayout.PropertyField(el.FindPropertyRelative("go"));



                 switch (DoShipChecking(SM, i))
                 {
                     case 0: break;

                     case 1:
                         GUILayout.Space(10);
                         GUILayout.BeginVertical("box");
                         EditorGUILayout.LabelField("Eship1");
                         GUILayout.Space(5);
                         EditorGUILayout.PropertyField(el.FindPropertyRelative("flypoints"), true);
                         EditorGUILayout.PropertyField(el.FindPropertyRelative("onfinish"), true);
                         GUILayout.EndVertical();
                         GUILayout.Space(10);
                         break;

                     case 4:
                         GUILayout.Space(10);
                         GUILayout.BeginVertical("box");
                         EditorGUILayout.LabelField("Eship4");
                         GUILayout.Space(5);
                         EditorGUILayout.PropertyField(el.FindPropertyRelative("flypoints"), true);
                         EditorGUILayout.PropertyField(el.FindPropertyRelative("onfinish"), true);
                         GUILayout.EndVertical();
                         GUILayout.Space(10);
                         break;
                 }


                 EditorGUILayout.PropertyField(el.FindPropertyRelative("Start_Wait"));
                 EditorGUILayout.PropertyField(el.FindPropertyRelative("Spawn_Wait"));
                 EditorGUILayout.PropertyField(el.FindPropertyRelative("Count"));
                 EditorGUILayout.PropertyField(el.FindPropertyRelative("spawntype"));

                 if (SM.holder[i].spawntype == SpawnType.Random)     **// exception error Here**
                 {
                     EditorGUILayout.PropertyField(el.FindPropertyRelative("randomdir"));
                 }

                 EditorGUILayout.PropertyField(el.FindPropertyRelative("Spawn_Pos"));

                 EditorGUI.indentLevel -= 1;
             }
         }


         EditorGUI.indentLevel -= 1;
     }


     //EditorGUILayout.PropertyField(serializedObject.FindProperty("objects"), true);

     if (EditorGUI.EndChangeCheck())
         serializedObject.ApplyModifiedProperties();
 }

 int DoShipChecking(SpawningMachyne SM, int i)
 {
     if (SM.holder[i].go.GetComponent<E_Ship_1>() != null)      **//  and another Here**
         return 1;
     if (SM.holder[i].go.GetComponent<E_Ship_4>() != null)
         return 4;

     return 0;
 }

}