XMLSerializer saves correctly, but loads incorrectly?

I'm making an inventory system for a Unity game.

It saves the inventory just fine, as you can see here: http://ift.tt/1AFCHQz

Here's my save-function:

public void SaveInventoryToXML()
{
    System.Xml.Serialization.XmlSerializer writer = new System.Xml.Serialization.XmlSerializer(typeof (List<Item>));
    System.IO.StreamWriter file = new System.IO.StreamWriter(inventoryPath);
    writer.Serialize(file, inventory);
    file.Close();
}

And the load-function:

public void LoadInventoryFromXML()
{
    System.Xml.Serialization.XmlSerializer reader = new System.Xml.Serialization.XmlSerializer(typeof(List<Item>));
    StreamReader sr = new StreamReader(inventoryPath);
    inventory = (List<Item>) reader.Deserialize(sr);
    sr.Close();
}

Here's the item class:

using UnityEngine;
using System.Collections.Generic;
using System.Runtime.InteropServices;

[System.Serializable] //what's with the square brackets
public class Item
{
    public string ItemName;
    public int ItemId;
    public string ItemDesc;
    public int BaseWorth;
    public int BaseDamage;
    public int RequiredLevel;
    public Sprite Sprite;
    public ItemType itemType;
    public ItemRarity itemRarity;
    public Weapon.WeaponType weaponType;
    public Weapon.AttackType attackType;
    public List<Enchantment> Enchantments;
    public bool Stackable;
    public int StackSize = 99;
    public int Amount = 1;

    public enum ItemType
    {
        Weapon, Consumable, Quest, Armor, Boots, Helmet, Gloves, Ring, Amulet
    }

    public enum ItemRarity
    {
        Common, Rare, Unique, Magic
    }

    public Item(string name, int id, int reqlvl, string desc, int baseworth, int basedamage, List<Enchantment> enchantments, ItemType itemtype, ItemRarity itemrarity, Sprite sprite )
    {
        ItemName = name;
        ItemId = id;
        RequiredLevel = reqlvl;
        ItemDesc = desc;
        BaseWorth = baseworth;
        BaseDamage = basedamage;
        Enchantments = enchantments;
        itemType = itemtype;
        itemRarity = itemrarity;
        Sprite = sprite;
        additionalParameters();
    }

    private void additionalParameters()
    {
        switch (itemType)
        {
            case ItemType.Consumable:
                Stackable = true;
                break;
        }
    }

    public Item()
    {
        ItemId = -1;
    }
}

And here's the enchantment class:

using UnityEngine;
using System.Collections;

public class Enchantment
{
    public EnchantmentType Type;
    public int Amount;
    public enum EnchantmentType
    {
        Fire, Ice, Poison, Electric, Brutalize, Greed, Invisiblity, Heal, ReplenishStamina, ReplenishMana,
        AddMaxHealth, AddMaxStamina, AddMaxMana
    }

    public Enchantment(EnchantmentType type, int amount)
    {
        Amount = amount;
        Type = type;
    }

    public Enchantment()
    {

    }
}

All the items are set to null, and I get a NullReferenceException. Here's the enormous error: http://ift.tt/1AFCGMz

What am I doing wrong?