Can't declare interface, name already in use

[Sim]

So: here's the two class files:

<?php

interface Item_Types
{
  
  public function __construct($data = array());
  
    public function getID();
    
  public function getValue();

  public function getName();

  public function getPrice();
  //return results or msg or whatevee you like, if type different from weapon, armour.
    public function useIT();

}

?>

<?php

class Weapon implements Item_Types{
  
  public $desc = "Increases attack power";
  public $itemType = "Weapon";
  public $itemID = null;
  public $name = null;
    public $value = 0;
    public $price = 0;
    public $data = array();
    
    //pass any data needed for item type to be used.
    public function __construct($data = array())
    {
      $this->data = $data;
      $this->itemID = $data['id'];
      $this->name = $data['name'];
      $this->value = $data['value'];
      $this->price = $data['price'];
    }
    
    public function getID(){
        return $this->itemID;
    }
    
  public function getValue(){
        return $this->value;
    }

  public function getName(){
    return $this->name;
  }

  public function getPrice(){
    
  }
  //returns value.
    public function useIT(){
      //was testing to see if could access properties
      global $db, $user;
      
      $user = new user(1, false);
      $user->set("US_money", $user->user->info->US_money + 10000);
      return $this->value;
    }
    
 
}

   include $ItemTypesDir . "ItemTypes.interface.php";
    include $ItemTypesDir . $iType["parentID"] . ".itemType.php";

 

Causes error:

There was an error!

File: /home/simmakew/public_html/GL/modules/installed/itemTypes/Types/ItemTypes.interface.php
Line: 3
Error: Cannot declare interface Item_Types, because the name is already in use
Type: E_RECOVERABLE_ERROR

 

But if I do this:

   //include $ItemTypesDir . "ItemTypes.interface.php";
    include $ItemTypesDir . $iType["parentID"] . ".itemType.php";

Comment the interface out. I get this error

There was an error!

File: /home/simmakew/public_html/GL/modules/installed/itemTypes/Types/Weapon.itemType.php
Line: 3
Error: Interface 'Item_Types' not found
Type: E_RECOVERABLE_ERROR

 

I highly doubt that there is any variable or object named Item_Types. I changed it t to that after I received the error to see if maybe I did declare something "ItemType" before changing, but I don't use _____ in any variables classes or any other objects.

   This fixed the error. 
     require_once($ItemTypesDir . "ItemTypes.interface.php");
    require_once($ItemTypesDir . $iType["parentID"] . ".itemType.php");