iTween Path-Constrained character loop trouble

Hi there! I would like to create the game with Pandemonium!-like control. There is a script from iTween Examples which allows me to implement it. However I ran into a trouble. When an object goes from point A to point C, the object jumps back to point A. Conversely, when the object point A, he jumps in C.

And one more trouble: physics doesn't work. Object ignores colliders. How can I fix this bugs?

 using UnityEngine;
 using System.Collections;
 
 public class pathController : MonoBehaviour {
     public Transform[] controlPath;
     public Transform character;
     public enum Direction {Forward,Reverse};
     
     private float pathPosition=0;
     private RaycastHit hit;
     public float speed = 0.1f;
     private float rayLength = 5;
     private Direction characterDirection;
     private Vector3 floorPosition;    
     private float lookAheadAmount = .01f;
     private float ySpeed=0;
     private float gravity=.5f;
     private float jumpForce=.12f;
     private uint jumpState=0; //0=grounded 1=jumping
     
     void OnDrawGizmos(){
         iTween.DrawPath(controlPath,Color.blue);    
     }    
     
     
     void Start(){
         //plop the character pieces in the "Ignore Raycast" layer so we don't have false raycast data:    
         //foreach (Transform child in character) {
             //child.gameObject.layer=2;
         //}
     }
     
     
     void Update(){
         DetectKeys();
         FindFloorAndRotation();
         MoveCharacter();
         MoveCamera();
 
     }
     
     
     void DetectKeys(){
         //forward path movement:
         if(Input.GetKeyDown(KeyCode.D)){
             characterDirection=Direction.Forward;
         
         }
         if(Input.GetKey(KeyCode.D)) {
             pathPosition += Time.deltaTime * speed;
         }
         
         //reverse path movement:
         if(Input.GetKeyDown(KeyCode.A)){
             characterDirection=Direction.Reverse;
 
         }
         if(Input.GetKey(KeyCode.A)) {
             //handle path loop around since we can't interpolate a path percentage that's negative(well duh):
             //float temp = pathPosition - (Time.deltaTime * speed);
             //if(temp<0){
             //    pathPosition=1;    
             //}else{
                 pathPosition -= (Time.deltaTime * speed);
             //}
         }    
         
         //jump:
         //if (Input.GetKeyDown("space") && jumpState==0) {
         //    ySpeed-=jumpForce;
         //    jumpState=1;
         //}
     }
     
     
     void FindFloorAndRotation(){
         float pathPercent = pathPosition%1;
         Vector3 coordinateOnPath = iTween.PointOnPath(controlPath,pathPercent);
         Vector3 lookTarget;
         
         //calculate look data if we aren't going to be looking beyond the extents of the path:
         if(pathPercent-lookAheadAmount>=0 && pathPercent+lookAheadAmount <=1){
             
             //leading or trailing point so we can have something to look at:
             if(characterDirection==Direction.Forward){
                 lookTarget = iTween.PointOnPath(controlPath,pathPercent+lookAheadAmount);
             }else{
                 lookTarget = iTween.PointOnPath(controlPath,pathPercent-lookAheadAmount);
             }
             
             //look:
             character.LookAt(lookTarget);
             
             //nullify all rotations but y since we just want to look where we are going:
             float yRot = character.eulerAngles.y;
             character.eulerAngles=new Vector3(0,yRot,0);
         }
         
         if (Physics.Raycast(coordinateOnPath,-Vector3.up,out hit, rayLength)){
             Debug.DrawRay(coordinateOnPath, -Vector3.up * hit.distance);
             floorPosition=hit.point;
         }
     }
     
     
     void MoveCharacter(){
         //add gravity:
         ySpeed += gravity * Time.deltaTime;
         
         //apply gravity:
         character.position=new Vector3(floorPosition.x,character.position.y-ySpeed,floorPosition.z);
         
         //floor checking:
         if(character.position.y<floorPosition.y){
             ySpeed=0;
             jumpState=0;
             character.position=new Vector3(floorPosition.x,floorPosition.y,floorPosition.z);
         }        
     }
     
     
     void MoveCamera(){
         iTween.MoveUpdate(Camera.main.gameObject,new Vector3(character.position.x,2.7f,character.position.z-5f),.9f);    
     }
 }