asp.net checkbox won't uncheck or vise versa

I have looked many different solutions but almost all of them are not what I am trying to do.

I have an aspx page that has 5 check boxes on it. I am pulling data from a SQL DB and setting the initial on/off state of the check box based on the retrieved value. This works fine.

The problem starts when I try to check or un-check a checkbox. If it is checked it will un-check for a split second and then the check returns or vise versa (Un-checked to to checked state).

Here are the check boxes:

<asp:CheckBox ID="ckbIVPO" runat="server" Text=" Invoice Value & P.O.#" OnCheckedChanged="ckbIVPO_CheckedChanged" AutoPostBack="true" />
<asp:CheckBox ID="ckbQuNotes" runat="server" Text=" Quality Notes" OnCheckedChanged="ckbQuNotes_CheckedChanged" AutoPostBack="true" />
<asp:CheckBox ID="ckbShipTerms" runat="server" Text=" Ship To & Shipping Terms" OnCheckedChanged="ckbShipTerms_CheckedChanged" AutoPostBack="true" />
<asp:CheckBox ID="ckbMatSurFin" runat="server" Text=" Material/Surface/Finish" OnCheckedChanged="ckbMatSurFin_CheckedChanged" AutoPostBack="true" />
<asp:CheckBox ID="ckbFabFasExt" runat="server" Text=" Fabrication & Fastner Extras" OnCheckedChanged="ckbFabFasExt_CheckedChanged" AutoPostBack="true" />

The OnCheckedChange event for each one is basically them same (Only control ID name changes:

If [control ID].Checked = checked Then
   [control ID].Checked = False
Else
    [Control ID].checked = True
End IF

I also found an article here on SO that talked about using hidden text boxes and setting the checkbox based on the value from it. But I can't seem to get that to work. I think I am missing something there.

Here is that code:

    If txbivpo.Text = "1" Then
        ckbIVPO.Checked = True
    Else
        ckbIVPO.Checked = False
    End If
    If txbshtrm.Text = "1" Then
        ckbShipTerms.Checked = True
    Else
        ckbShipTerms.Checked = False
    End If
    If txbqunotes.Text = "1" Then
        ckbQuNotes.Checked = True
    Else
        ckbQuNotes.Checked = False
    End If
    If txbmatsurfin.Text = "1" Then
        ckbMatSurFin.Checked = True
    Else
        ckbMatSurFin.Checked = False
    End If
    If txbfabfasext.Text = "1" Then
        ckbFabFasExt.Checked = True
    Else
        ckbFabFasExt.Checked = False
    End If

I just can't seem to get this to work. I am sure that I am missing something but I am not sure what it is. I am also not set in stone as to doing it this way. I am using VB because I am not very good with C#. (Actually I flat out suck at C#!) I am using the hidden text boxes to pull the data for the update query if the user changes something and I need to update the SQL.

Can anyone help me or point me to a clear example of how to simply have the check box change state, and stay, and then be able to update the hidden text box so the query will update correctly?