Three.js controlling shadows

I'm having trouble controlling shadows in THREE.js. First off, the shadow in my scene is way too dark. From what I've read, there was a shadowDarkness property, that is know longer available in the current version of three.js. Does anyone know a work around?

Also, in the attached image: the "backface" geometry is not occluding light on the shadow of the seat - however, you can see the backface of the stool in the reflection of the sphere(cubeCamera). Does anyone know how to fix that?

On a side note: chrome gives me an error "Uncaught TypeError: Cannot set property 'visible' of undefined," regarding the

 frameMesh.visible = false;
    cubeCameraFrame.position.copy(frameMesh.position);
    cubeCameraFrame.updateCubeMap(renderer, scene);
    frameMesh.visible = true;

part of my code. Could that be effecting the shadows in some way? I can comment that part of the code and it will have little effect on the stoolframes "reflective" appearance. However it then no longer is reflects in the sphere. Any help is much appreciated.

///webGL - Locking down the Basics
/////////////////////////////////////////////////////////////Environment Settings///////////////////////////////////////////////////////////////////////
///Renderer 
var scene = new THREE.Scene();

var renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.shadowMapType = THREE.PCFSoftShadowMap;
renderer.shadowMapEnabled = true;

document.body.appendChild(renderer.domElement);

///Camera's
var camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
scene.add(camera);

camera.position.set(0, 16, 25);
camera.rotation.x += -0.32;

var cubeCameraSphere = new THREE.CubeCamera(1, 1000, 256); // parameters: near, far, resolution
cubeCameraSphere.renderTarget.texture.minFilter = THREE.LinearMipMapLinearFilter; // mipmap filter
scene.add(cubeCameraSphere);

var cubeCameraFrame = new THREE.CubeCamera(1, 1000, 256); // parameters: near, far, resolution
cubeCameraFrame.renderTarget.texture.minFilter = THREE.LinearMipMapLinearFilter; // mipmap filter
scene.add(cubeCameraFrame);

///Controls



///Lights


var lightSpot_Right = new THREE.SpotLight(0xffffff);
lightSpot_Right.position.set(50, 50, 0);
lightSpot_Right.intensity = 1.25;
lightSpot_Right.castShadow = true;

lightSpot_Right.shadowDarkness = 0.1;

lightSpot_Right.shadowMapWidth = 2048;
lightSpot_Right.shadowMapHeight = 2048;

lightSpot_Right.shadowCameraNear = 1;
lightSpot_Right.shadowCameraFar = 100;
lightSpot_Right.shadowCameraFov = 65;
scene.add(lightSpot_Right);

var lightDirect_Left = new THREE.DirectionalLight(0xffffff, 0.25);
lightDirect_Left.position.set(-1, 0, 0);
scene.add(lightDirect_Left);

///Loaders
var loadTexture = new THREE.TextureLoader();
var loader = new THREE.JSONLoader();

///skyBox
var imagePrefix = "textures/";
var directions = ["skyboxRight", "skyboxLeft", "skyboxTop", "skyboxBottom", "skyboxFront", "skyboxBack"];
var imageSuffix = ".jpg";

var skyMaterialArray = [];
for (var i = 0; i < 6; i++)
    skyMaterialArray.push(new THREE.MeshBasicMaterial({
        map: new THREE.TextureLoader().load(imagePrefix + directions[i] + imageSuffix),
        side: THREE.BackSide
    }));
var skyMaterial = new THREE.MeshFaceMaterial(skyMaterialArray);


var skyGeometry = new THREE.CubeGeometry(1000, 1000, 1000);
var skyBox = new THREE.Mesh(skyGeometry, skyMaterial);
scene.add(skyBox);


////////////////////////////////////////////////////////Object Settings//////////////////////////////////////////////////////////////////

//Textures
var seatTexture = loadTexture.load("textures/Maharam_Mister_Notice_Diffuse.jpg");
seatTexture.wrapS = THREE.RepeatWrapping;
seatTexture.wrapT = THREE.RepeatWrapping;
seatTexture.repeat.set(3, 3);

var conceteDiffuse = loadTexture.load("textures/Contrete_Diffuse.jpg");
conceteDiffuse.wrapS = THREE.RepeatWrapping;
conceteDiffuse.wrapT = THREE.RepeatWrapping;
conceteDiffuse.repeat.set(3, 3);
var conceteNormal = loadTexture.load("textures/Contrete_Normal.jpg");
conceteNormal.wrapS = THREE.RepeatWrapping;
conceteNormal.wrapT = THREE.RepeatWrapping;
conceteNormal.repeat.set(3, 3);
var conceteSpecular = loadTexture.load("textures/Contrete_Specular.jpg");
conceteSpecular.wrapS = THREE.RepeatWrapping;
conceteSpecular.wrapT = THREE.RepeatWrapping;
conceteSpecular.repeat.set(3, 3);

///Materials
var seatMaterial = new THREE.MeshLambertMaterial({
    map: seatTexture,
    side: THREE.DoubleSide
});
var frameMaterial = new THREE.MeshPhongMaterial({
    envMap: cubeCameraFrame.renderTarget,
    color: 0xcccccc,
    emissive: 0x404040,
    shininess: 10,
    reflectivity: .8
});
var frameHardwareMat = new THREE.MeshPhongMaterial({
    color: 0x000000
});
var feetMat = new THREE.MeshPhongMaterial({
    color: 0x050505,
    shininess: 99
});

var sphereMat = new THREE.MeshPhongMaterial({
    envMap: cubeCameraSphere.renderTarget

});

var groundMat = new THREE.MeshPhongMaterial({
    map: conceteDiffuse,
    specularMap: conceteSpecular,
    normalMap: conceteNormal,
    normalScale: new THREE.Vector2( 0.0, 0.6 ),
    shininess: 50
});

///Geometry and Meshes
var barStool = new THREE.Object3D();
scene.add(barStool);

var seatMesh;
loader.load("models/stoolSeat.js", function (geometry, material) {
    seatMesh = new THREE.Mesh(geometry, seatMaterial);
    seatMesh.scale.set(.5, .5, .5);
    seatMesh.castShadow = true;
    seatMesh.receiveShadow = true;
    barStool.add(seatMesh);

});

var frameMesh;
loader.load("models/stoolFrame.js", function (geometry, material) {
    frameMesh = new THREE.Mesh(geometry, frameMaterial);
    frameMesh.scale.set(.5, .5, .5);
    frameMesh.castShadow = true;
    barStool.add(frameMesh);
});

var frameFeetMesh;
loader.load("models/stoolFeet.js", function (geometry, material) {
    frameFeetMesh = new THREE.Mesh(geometry, feetMat);
    frameFeetMesh.scale.set(.5, .5, .5);
    frameFeetMesh.castShadow = true;
    barStool.add(frameFeetMesh);
});

var frameHardwareMesh;
loader.load("models/stoolHardware.js", function (geomtry, material) {
    frameHardwareMesh = new THREE.Mesh(geomtry, frameHardwareMat);
    frameHardwareMesh.scale.set(.5, .5, .5);
    barStool.add(frameHardwareMesh);
});


var sphereGeo = new THREE.SphereGeometry(2.5, 50, 50);
var sphereMesh = new THREE.Mesh(sphereGeo, sphereMat);
scene.add(sphereMesh);

sphereMesh.position.set(-10, 5, 0);

var groundGeo = new THREE.PlaneGeometry(100, 50, 1);
var groundMesh = new THREE.Mesh(groundGeo, groundMat);
scene.add(groundMesh);

groundMesh.rotation.x = -90 * Math.PI / 180;
groundMesh.receiveShadow = true;

///Render Scene

var render = function () {

    requestAnimationFrame(render);
    barStool.rotation.y += 0.01;
    skyBox.rotation.y -= 0.0002;

    sphereMesh.visible = false;
    cubeCameraSphere.position.copy(sphereMesh.position);
    cubeCameraSphere.updateCubeMap(renderer, scene);
    sphereMesh.visible = true;

    //frameMesh.visible = false;
    //cubeCameraFrame.position.copy(frameMesh.position);
    //cubeCameraFrame.updateCubeMap(renderer, scene);
    //frameMesh.visible = true;

    renderer.render(scene, camera);
};

render();

Shadow darkness has been removed. The best work-around is to add ambient light to your scene.

scene.add( new THREE.AmbientLight( 0xffffff, 0.3 );

You may want to concurrently reduce the intensity of your SpotLight.

The shadow is actually correct given only back faces are casting shadows. It appears that the stool is hollow under the seat -- in other words, the seat is not a closed volume. Add a bottom to the underside of your seat.

Alternatively, you can leave your model as-is and experiment with

renderer.shadowMap.cullFace = THREE.CullFaceNone;

Finally, you are getting the error because you are accessing frameMesh in the animation loop before it is defined in the loader callback. The callback is asynchronous.

if ( frameMesh !== undefined ) {
    // your code
}

three.js r.75