creating a save editor ( problem with hex) Record of Agarest War Zero

I am a new member and i have some VB and C# knowledges.
Recently i started a project to make a save editor to help the community with games that are not popular.

Record of Agarest War Zero is a J-RPG and because this is very hard to find something about how to make a save editor of this game, so i am making for us but a i have a problem.

Imports PackageIO

Public Class Form1

Dim Open As New OpenFileDialog
Dim filepath As String = Open.FileName

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub

Private Sub open1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles open1.Click
If Open.ShowDialog = Windows.Forms.DialogResult.OK Then
filepath = Open.FileName
readfile()
End If
End Sub
Public Sub readfile()
Try
Dim reader As New PackageIO.Reader(filepath, PackageIO.Endian.Big)
NumericUpDown1.Enabled = True
save.Enabled = True
reader.Position = &H836E0
NumericUpDown1.Text = reader.ReadInt32

Catch ex As Exception
MessageBox.Show("error")
NumericUpDown1.Enabled = False
save.Enabled = False
End Try
End Sub

Private Sub save_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles save.Click
Try
Dim Writer As New PackageIO.Writer(filepath, Endian.Big)
Writer.Position = &H836E0
Writer.WriteInt32(NumericUpDown1.Value)
MsgBox("saved!")
Catch ex As Exception
MsgBox("error", MsgBoxStyle.OkOnly, "try again")
End Try
End Sub
End Class

I can read the memory position and write in the save, but when i load the save, does not work, for example. The video game stays in a "Black Screen". i dont know how to solve this problem,


This Hexadecimal 836E0 is the position of EP (experience points).