Error : ArgumentException , NullReferenceException

Hi,
Maybe I should be posting over here for support issue .
( posted at unity forum http://forum.unity3d.com/threads/random-dungeon-generator-for-unity.174147/page-3 )
I'm having the errors :-
ArgumentException: Getting control 6's position in a group with only 6 controls when doing Repaint
Aborting
UnityEngine.GUILayoutGroup.GetNext () (at C:/BuildAgent/work/aeedb04a1292f85a/artifacts/EditorGenerated/GUILayoutUtility.cs:513)
UnityEngine.GUILayoutUtility.DoGetRect (Single minWidth, Single maxWidth, Single minHeight, Single maxHeight, UnityEngine.GUIStyle style, UnityEngine.GUILayoutOption[] options) (at C:/BuildAgent/work/aeedb04a1292f85a/artifacts/EditorGenerated/GUILayoutUtility.cs:306)
UnityEngine.GUILayoutUtility.GetRect (Single minWidth, Single maxWidth, Single minHeight, Single maxHeight, UnityEngine.GUIStyle style, UnityEngine.GUILayoutOption[] options) (at C:/BuildAgent/work/aeedb04a1292f85a/artifacts/EditorGenerated/GUILayoutUtility.cs:297)
UnityEditor.EditorGUILayout.GetControlRect (Boolean hasLabel, Single height, UnityEngine.GUIStyle style, UnityEngine.GUILayoutOption[] options) (at C:/BuildAgent/work/aeedb04a1292f85a/Editor/Mono/EditorGUI.cs:6009)
UnityEditor.EditorGUILayout.GetControlRect (Boolean hasLabel, Single height, UnityEngine.GUILayoutOption[] options) (at C:/BuildAgent/work/aeedb04a1292f85a/Editor/Mono/EditorGUI.cs:6004)
UnityEditor.PropertyHandler.OnGUILayout (UnityEditor.SerializedProperty property, UnityEngine.GUIContent label, Boolean includeChildren, UnityEngine.GUILayoutOption[] options) (at C:/BuildAgent/work/aeedb04a1292f85a/Editor/Mono/ScriptAttributeGUI/PropertyHandler.cs:193)

and these errors  :-
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.EditorGUI.BeginProperty (Rect totalPosition, UnityEngine.GUIContent label, UnityEditor.SerializedProperty property) (at C:/BuildAgent/work/aeedb04a1292f85a/Editor/Mono/EditorGUI.cs:3856)
UnityEditor.EditorGUI.DefaultPropertyField (Rect position, UnityEditor.SerializedProperty property, UnityEngine.GUIContent label) (at C:/BuildAgent/work/aeedb04a1292f85a/Editor/Mono/EditorGUI.cs:4343)
UnityEditor.PropertyHandler.OnGUI (Rect position, UnityEditor.SerializedProperty property, UnityEngine.GUIContent label, Boolean includeChildren) (at C:/BuildAgent/work/aeedb04a1292f85a/Editor/Mono/ScriptAttributeGUI/PropertyHandler.cs:144)
UnityEditor.EditorGUI.PropertyFieldInternal (Rect position, UnityEditor.SerializedProperty property, UnityEngine.GUIContent label, Boolean includeChildren) (at C:/BuildAgent/work/aeedb04a1292f85a/Editor/Mono/EditorGUI.cs:4338)
UnityEditor.EditorGUI.PropertyField (Rect position, UnityEditor.SerializedProperty property, UnityEngine.GUIContent label, Boolean includeChildren) (at C:/BuildAgent/work/aeedb04a1292f85a/artifacts/EditorGenerated/EditorGUIBindings.cs:711)
UnityEditor.EditorGUI.PropertyField (Rect position, UnityEditor.SerializedProperty property, UnityEngine.GUIContent label) (at C:/BuildAgent/work/aeedb04a1292f85a/artifacts/EditorGenerated/EditorGUIBindings.cs:706)
GenericChoiceDrawer.OnGUI (Rect position, UnityEditor.SerializedProperty property, UnityEngine.GUIContent label) (at Assets/Daedalus_Core/Editor/Daedalus_Editor/GenericChoiceDrawer.cs:60)



any helps ?
Thanks !