Custom Save Button On Form Preventing Subform

I have a main form and a sub form. Tbhidden and tbpropersave are the text boxes that govern the update procedure. The main form has two text box that i use to prevent the user from modifying the information on the main form without clicking my custom save button. the problem is that the subform should be completed after the information on the main form has been filled in. The Update code i have refuses to allow me to complete the subform without first clicking the save button on the main form. Here is the code. I wana be able to fill in info in the main form, then the sub form then click save. The sub form is a table which relates to the main form table Many to One.

Private Sub Form_BeforeUpdate(Cancel As Integer)
On Error GoTo Err_Form_BeforeUpdate

Me.tbhidden.SetFocus

If Me.tbPropersave.Value = "No" Then
Beep
MsgBox "Please Save This Record!" & vbCrLf & vbLf & "You can not advance to another record until you either 'Save' the changes made to this record or 'Undo' your changes.", vbExclamation, "Save Required"
DoCmd.CancelEvent
Exit Sub
End If

Exit_Form_BeforeUpdate:
Exit Sub

Err_Form_BeforeUpdate:
If Err = 3020 Then 'Update or CancelUpdate without AddNew or Edit
Exit Sub
Else
MsgBox Err.Number, Err.Description
Resume Exit_Form_BeforeUpdate
End If



Please HELP


End Sub