About AVL tree rotation logic

I am trying to create an AVL tree, the most importation is rotation. I used my sample data but the result is wrong in the first rotation.

I think the error is that I didn't return the correct object after rotation. Please help me to look at it.

namespace AVLTree
{
    public class AVLTree
    {
        private AvlTreeNode root;
        // AvlTreeNode has three fields, data, left and right.
        public AVLTree()
        {
            root = null;
        }

        public void Insert(int value)
        {
            Insert(value, ref root);
            if (!IsBanlance(root))
                ReBanlance(root);
        }

        private void Insert(int element, ref AvlTreeNode node)
        {
           // blah blah
        }

        public void ReBanlance(AvlTreeNode node)
        {
            int heightDiff = GetHeight(node.left) - GetHeight(node.right);
            if (heightDiff > 1)//left case
            {
                if (GetHeight(node.left.left) > GetHeight(node.left.right))//left left case
                {
                    RightRotation(node);
                }
                else// left right case
                {
                    LeftRotation(node);
                    RightRotation(node);
                }
            }
            else if (heightDiff < -1)//right case
            {
                if (GetHeight(node.right.left) > GetHeight(node.right.right))//right left case
                {
                    RightRotation(node);
                    LeftRotation(node);
                }
                else//right right case
                {
                    LeftRotation(node);
                    RightRotation(node);
                }
            }
            return true;
        }

        // http://en.wikipedia.org/wiki/Tree_rotation
        // Left Rotation of node P:
        // Let Q be P's right child.
        // Set Q to be the new root.
        // Set P's right child to be Q's left child.
        // Set Q's left child to be P.

        public bool LeftRotation(AvlTreeNode P)
        {
            // Define new instances
            AvlTreeNode Q = new AvlTreeNode();
            AvlTreeNode A = new AvlTreeNode();
            AvlTreeNode B = new AvlTreeNode();
            AvlTreeNode C = new AvlTreeNode();
            // Original tree expression
            Q = P.right;
            A = P.left;
            B = Q.left;
            C = Q.right;
            //  Begin rotation
            P.left = A;
            P.right = B;
            Q.left = P;
            Q.right = C;
            return true;
        }

        //    Right Rotation of node Q:
        //    Let P be Q's left child.
        //    Set P to be the new root.
        //    Set Q's left child to be P's right child.
        //    Set P's right child to be Q.

        public bool RightRotation(AvlTreeNode Q)
        {
            // Define new instances
            AvlTreeNode P = new AvlTreeNode();
            AvlTreeNode A = new AvlTreeNode();
            AvlTreeNode B = new AvlTreeNode();
            AvlTreeNode C = new AvlTreeNode();
            // Original tree expression
            P = Q.left;
            A = P.left;
            B = P.right;
            C = Q.right;
            //  Begin rotation
            P.left = A;
            Q.right = C;
            Q.left = B;
            P.right = Q;
            return true;
        }