Trying to migrate older version to newer one

but getting an error 'unexpected row count 0 expected 1 nhibernate'

Parent Class

using System.Collections;
using Iesi.Collections;
using Nullables;
using Utility;
using System;

namespace Business
{
/// <summary>
/// Summary description for Contact.
/// </summary>
public class Contact
{
private int id;
private string lastName;
private string firstName;
private string middleName;
private string fullName;
private string initials;
private bool isActive;
private string title;
private string greeting;
private string company;
private string notes;
private Nullable<Int32> lastChangedUserId;
private Nullable<DateTime> lastChangedDate;
private string lastChangedReason;

private IList addresses;

//getters and setters


public virtual IList Addresses
{
get
{
if(addresses == null)
addresses = new ArrayList();

return addresses;
}
set { addresses = value; }
}



public virtual void AddAddress(ContactAddress address)
{
address.Contact = this;
Addresses.Add(address);
}





public virtual void Save(int changedByUserId)
{
lastChangedReason = "";
this.lastChangedUserId = changedByUserId;
this.lastChangedDate = DateTime.Today;
Save(this);
}


public virtual void Delete()
{
Delete(this);
}

public static void Save(Contact contact)
{
DbSessionFactory.DbSession(DbType.So).SaveOrUpdate(contact);
}

public static void Delete(Contact contact)
{
DbSessionFactory.DbSession(DbType.So).Delete(contact);
}

public static Contact Get(int contactId)
{
return (Contact) DbSessionFactory.DbSession(DbType.So).GetObjectById(typeof (Contact), contactId);
}

public static IList List()
{
return DbSessionFactory.DbSession(DbType.So).GetObjectList(typeof (Contact));
}

public static IList DisplayList()
{
string sql = "from Contact c order by c.LastName, c.FirstName";
return DbSessionFactory.DbSession(DbType.So).CurrentSession.CreateQuery(sql).List();
}
}
}

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="Business.Contact, Business" table="Contact">
<id name="Id" type="Int32" unsaved-value="0">
<column name="ContactID" unique="true" index="PK_FieldMap"/>
<generator class="native" />
</id>

<property name="LastName" column="LastName"/>
<property name="FirstName" column="FirstName"/>
<property name="MiddleName" column="MiddleName"/>
<property name="FullName" column="FullName"/>
<property name="Initials" column="Initials"/>
<property name="IsActive" column="ContactActive" not-null="true" />
<property name="Title" column="Title"/>
<property name="Greeting" column="Greeting"/>
<property name="Company" column="Company"/>
<property name="Notes" column="Notes"/>
<property name="LastChangedUserId" column="LastChangedUser" type="System.Nullable`1[[System.Int32, mscorlib]], mscorlib"/>
<property name="LastChangedDate" column="LastChangedDate" type="System.Nullable`1[[System.DateTime, mscorlib]], mscorlib"/>
<property name="LastChangedReason" column="LastChangedReason"/>

<bag name="Addresses" cascade="delete-orphan" lazy="true" inverse="true">
<key column="ContactID" />
<one-to-many class="Business.ContactAddress, Business" />
</bag>



</class>
</hibernate-mapping>


Child class

using System;
using System.Collections;
using Utility;
using Nullables;
using NHibernate;
using NHibernate.Classic;

namespace Business
{
/// <summary>
/// Summary description for ContactAddress.
/// </summary>
public class ContactAddress : NHibernate.Classic.ILifecycle
{
#region ILifeCycle Implementation
public virtual LifecycleVeto OnSave(ISession session)
{
return LifecycleVeto.NoVeto;
}

public virtual LifecycleVeto OnUpdate(ISession session)
{
return LifecycleVeto.NoVeto;
}

public virtual LifecycleVeto OnDelete(ISession session)
{
return LifecycleVeto.NoVeto;
}

public virtual void OnLoad(ISession session, object oObject)
{
this.m_isChanged = false;
}
;
#endregion


private bool m_isChanged;

private int id;
private string name;
private string address1;
private string address2;
private string city;
private string state;
private string zip;
private string country;
private bool isPrimary;
private Contact contact;
private string m_lastchangeduser;
private Nullable<DateTime> m_lastchangeddate;
private string m_lastchangedreason;


private IList divisions;

//getters and setters
public virtual Contact Contact
{
get { return contact; }
set { contact = value; }
}

/// <summary>
/// Returns whether or not the object has changed it's values.
/// </summary>
public virtual bool IsChanged
{
get
{
return m_isChanged;
}

set
{
m_isChanged = value;
}
}


public virtual IList Divisions
{
get
{
if(divisions == null)
divisions = new ArrayList();
return divisions;
}
set
{
divisions = value;
}
}

public virtual void Save()
{
// as always and just update the DateTime stuff if needed.
if (m_isChanged)
{
LastChangedDate = DateTime.Today;
LastChangedUser = Utility.UserSettings.Current.Username;
}

Save(this);
m_isChanged = false;
}

public virtual void Delete()
{
Delete(this);
}


public static void Save(ContactAddress address)
{
DbSessionFactory.DbSession.SaveOrUpdate(address);
}

public static void Delete(ContactAddress address)
{
DbSessionFactory.DbSession.Delete(address);
}
}
}

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class
name="Business.ContactAddress, Business"
table="ContactAddress">
<id name="Id" column="ContactAddressID" type="Int32" unsaved-value="0">
<generator class="native" />
</id>
<property name="Name" column="ContactAddressName"/>
<property name="Address1" column="Address"/>
<property name="Address2" column="Address2"/>
<property name="City" column="City"/>
<property name="State" column="State"/>
<property name="Zip" column="ZipCode"/>
<property name="Country" column="Country"/>
<property name="IsPrimary" column="IsPrimary" />
<property column="LastChangedUser" type="String" name="LastChangedUser" />
<property column="LastChangedDate" type="System.Nullable`1[[System.DateTime, mscorlib]], mscorlib" name="LastChangedDate" />
<property column="LastChangedReason" type="String" name="LastChangedReason" />
<bag name="Divisions" lazy="true" cascade="none" table="DivisionAddress">
<key column="ContactAddressId"></key>
<many-to-many class="Business.Division, Business" column="DivisionId" />
</bag>
<many-to-one name="Contact" column="ContactID" class="Business.Contact, Business" />
</class>
</hibernate-mapping>

on save in UI saving like this

private void savecontact(Contact contact)
{

DbSessionFactory.DbSession.FlushSession();
DbSessionFactory.DbSession.CloseSession();
DbSessionFactory.DbSession.OpenSession();

Contact contact = Contact.Get(contactId);

ArrayList newAddresses = new ArrayList();
ArrayList newAddressIds = new ArrayList();

for (int i = 0; i < addressDataSource.Rows.Count; i++ )
{
datarow row = addressDataSource.Rows[i];
int addressId = (int)row.GetCellValue("AddressId");


ContactAddress address;
if (addressId > 0)
{
address = ContactAddress.Get(addressId);
if (address != null)
{
newAddressIds.Add(addressId);
}
else
{
address = new ContactAddress();
//newAddressIds.Add(addressId);
}
}
else
{
address = new ContactAddress();
}

if (address != null)
{
// address details entererd

newAddresses.Add(address);
}
}

foreach(ContactAddress address in contact.Addresses)
{
bool found = false;
foreach(int addressId in newAddressIds)
{
if(addressId == address.Id || addressId == 0)
{
found = true;
break;
}
}

if(!found)
{
if (ContactAddressRemoved != null)
ContactAddressRemoved(this, new AddressDeletedEventArgs(address));

address.Delete();
//address.Divisions.Clear();
}
}

contact.Addresses.Clear();


foreach (ContactAddress address in newAddresses)
{
address.Save();
contact.Addresses.Add(address);
}

contact.Save(UserUtil.CurrentUser);
}

thank you,
Vidya