Error compiler unity

Errorr compiler unity:

Assets/Editor/Image Effects/CameraMotionBlurEditor.js(92,36): BCE0004: Ambiguous Reference 'Preview':CameraMotionBlurEditor.Preview, UnityEditor.Editor.Preview.

Assets/Editor/Image Effects/CameraMotionBlurEditor.js(93,9): BCE0004: Ambiguous Reference 'Preview':CameraMotionBlurEditor.Preview, UnityEditor.Editor.Preview.

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#pragma strict

@CustomEditor (CameraMotionBlur)
class CameraMotionBlurEditor extends Editor
{
var serObj : SerializedObject;

var filterType : SerializedProperty;
var preview : SerializedProperty;
var previewScale : SerializedProperty;
var movementScale : SerializedProperty;
var jitter : SerializedProperty;
var rotationScale : SerializedProperty;
var maxVelocity : SerializedProperty;
var minVelocity : SerializedProperty;
var maxNumSamples : SerializedProperty;
var velocityScale : SerializedProperty;
var velocityDownsample : SerializedProperty;
var noiseTexture : SerializedProperty;
var showVelocity : SerializedProperty;
var showVelocityScale : SerializedProperty;
var excludeLayers : SerializedProperty;
//var dynamicLayers : SerializedProperty;

function OnEnable () {
serObj = new SerializedObject (target);

filterType = serObj.FindProperty ("filterType");

preview = serObj.FindProperty ("preview");
previewScale = serObj.FindProperty ("previewScale");

movementScale = serObj.FindProperty ("movementScale");
rotationScale = serObj.FindProperty ("rotationScale");

maxVelocity = serObj.FindProperty ("maxVelocity");
minVelocity = serObj.FindProperty ("minVelocity");

maxNumSamples = serObj.FindProperty ("maxNumSamples");
jitter = serObj.FindProperty ("jitter");

excludeLayers = serObj.FindProperty ("excludeLayers");
//dynamicLayers = serObj.FindProperty ("dynamicLayers");

velocityScale = serObj.FindProperty ("velocityScale");
velocityDownsample = serObj.FindProperty ("velocityDownsample");

noiseTexture = serObj.FindProperty ("noiseTexture");
}

function OnInspectorGUI () {
serObj.Update ();

EditorGUILayout.LabelField("Simulates camera based motion blur", EditorStyles.miniLabel);

EditorGUILayout.PropertyField (filterType, new GUIContent("Technique"));
if (filterType.enumValueIndex == 3 && !(target as CameraMotionBlur).Dx11Support()) {
EditorGUILayout.HelpBox("DX11 mode not supported (need shader model 5)", MessageType.Info);
}
EditorGUILayout.PropertyField (velocityScale, new GUIContent(" Velocity Scale"));
if(filterType.enumValueIndex >= 2) {
EditorGUILayout.LabelField(" Tile size used during reconstruction filter:", EditorStyles.miniLabel);
EditorGUILayout.PropertyField (maxVelocity, new GUIContent(" Velocity Max"));
}
else
EditorGUILayout.PropertyField (maxVelocity, new GUIContent(" Velocity Max"));
EditorGUILayout.PropertyField (minVelocity, new GUIContent(" Velocity Min"));

EditorGUILayout.Separator ();

EditorGUILayout.LabelField("Technique Specific");

if(filterType.enumValueIndex == 0) {
// portal style motion blur
EditorGUILayout.PropertyField (rotationScale, new GUIContent(" Camera Rotation"));
EditorGUILayout.PropertyField (movementScale, new GUIContent(" Camera Movement"));
}
else {
// "plausible" blur or cheap, local blur
EditorGUILayout.PropertyField (excludeLayers, new GUIContent(" Exclude Layers"));
EditorGUILayout.PropertyField (velocityDownsample, new GUIContent(" Velocity Downsample"));
velocityDownsample.intValue = velocityDownsample.intValue < 1 ? 1 : velocityDownsample.intValue;
if(filterType.enumValueIndex >= 2) { // only display jitter for reconstruction
EditorGUILayout.PropertyField (noiseTexture, new GUIContent(" Sample Jitter"));
EditorGUILayout.PropertyField (jitter, new GUIContent(" Jitter Strength"));
}
}

EditorGUILayout.Separator ();

EditorGUILayout.PropertyField (preview, new GUIContent("Preview"));
if (preview.boolValue)
EditorGUILayout.PropertyField (previewScale, new GUIContent(""));

serObj.ApplyModifiedProperties();
}
}

 

When you're doing "new GUIContent("Preview")", Unity doesn't know if you want a CameraMotionBlurEditor.Preview or a UnityEditor.Editor.Preview. That's what Ambiguous Reference error means - a reference can refer to more than one class. Either rename your class, or qualify your reference (e.g. try "new GUIContent("UnityEditor.Editor.Preview")")