Access / VBA - Are Form Properties keeping my tables open?

Question

UPDATE: I've done some more testing and disabled the button I added, the form still will not close the connection when I close the form. I'm thinking it has more to do with the form properties then the code behind the button, or perhaps the button code and form have conflicting properties keeping the table open.

I also tried to set the rs = Nothing and db = Nothing after I close the connections in the VBA.

So i have a sub-form, that gets called by my Mainform. When this happens I try and populate some controls using the VBA code below. However, when i close the sub-form, and try and re-access the sub-form from the Mainform, it says :

Private Sub CommandDupe_Click()
Dim db As DAO.Database, rs As DAO.Recordset
Dim strSQL As String

Set db = CurrentDb()
strSQL = "SELECT TOP 1 CPOrders.Cust, Customer.NAME, CPOrders.CP_Ref, CPOrders.Slsman, CPOrders.Date_opn, CPOrders.CPSmall, CPOrders.InvIssu, CPOrders.InvNo, CPOrders.InvDate, CPOrders.DueDate, CPOrders.ETADate, CPOrders.Closed, CPOrders.Cust, CPOrders.Name, CPOrders.BuyerRef, CPOrders.ToCity, CPOrders.ToState, CPOrders.ToCtry, CPOrders.ToPort, CPOrders.Supplier, CPOrders.Origin, CPOrders.Product, CPOrders.GradeType, CPOrders.NoUnits, CPOrders.Pkg, CPOrders.Qty, CPOrders.TotSale, CPOrders.TotCost, CPOrders.GrMargin, CPOrders.[Sale$/Unit], CPOrders.[Cost$/Unit], CPOrders.OceanCost, CPOrders.OceanNotes, CPOrders.BLadingDate, CPOrders.USAPort, CPOrders.FOBCost, CPOrders.FASExportVal, CPOrders.InlandFrt, CPOrders.CommodCode, CPOrders.Notes, CPOrders.ProjCust, CPOrders.ProjValue, CPOrders.ContainerNumber, CPOrders.Vessel, CPOrders.Ord_Terms, CPOrders.Invoice_ID FROM Customer INNER JOIN CPOrders ON Customer.[CUST_#] = CPOrders.Cust ORDER BY CPOrders.Invoice_ID desc;"
Set rs = db.OpenRecordset(strSQL, dbOpenDynaset, dbReadOnly)
rs.MoveFirst


CP_Ref.Value = rs("CP_Ref")
Slsman.Value = rs("Slsman")
Date_opn.Value = rs("Date_opn")
CPSmall.Value = rs("CPSmall")
InvIssu.Value = rs("InvIssu")
InvNo.Value = rs("InvNo")
InvDate.Value = rs("InvDate")
DueDate.Value = rs("DueDate")
Cust.Value = rs("Cust")
BuyerRef.Value = rs("BuyerRef")
ToCity.Value = rs("ToCity")
ToState.Value = rs("ToState")
ToCtry.Value = rs("ToCtry")
ToPort.Value = rs("ToPort")
Product.Value = rs("Product")
Supplier.Value = rs("Supplier")
GradeType.Value = rs("GradeType")
Origin.Value = rs("Origin")
NoUnits.Value = rs("NoUnits")
Pkg.Value = rs("Pkg")
Qty.Value = rs("Qty")
TotSale.Value = rs("TotSale")
TotCost.Value = rs("TotCost")
OceanCost.Value = rs("OceanCost")
OceanNotes.Value = rs("OceanNotes")
BLadingDate.Value = rs("BLadingDate")
USAPort.Value = rs("USAPort")
FOBCost.Value = rs("FOBCost")
Notes.Value = rs("Notes")
InlandFrt.Value = rs("InlandFrt")
CommodCode.Value = rs("CommodCode")
Vessel.Value = rs("Vessel")
ContainerNumber.Value = rs("ContainerNumber")
ProjCust.Value = rs("ProjCust")
ProjValue.Value = rs("ProjValue")


rs.Close
db.Close

As you can see I do close the rs and the db...what else can i do to make sure this connection is closed after I close the sub-form? I need to be able to access this from the MainForm consistently.

Thanks in advance!!! Also I added the form properties of the form that does not close