Recordset Locking?

Hi everyone,

I have a form on which I am unable to enter data. My feeling
is that it is because the recordset is locked (the text areas
are not locked).

Here's the background info:


I have 3 forms and tables that work off of one another.

CustomerInfo
SystemRecord
ServiceHistory

A CustomerInfo record must exist in order to add a SystemRecord record, and both must exist in order to add a Service History record.

Here's the example.

I had a ServiceRecord record and I click on the button to
open the ServiceHistory form to add a record. Since no
record exists, I want the 4 key fields to have values from the ServiceRecord table. So after many tries, this is the
code I came up with:

Private Sub Form_Open(Cancel As Integer)


If IsNull(Me.txtSystemID) Or IsNull(Me.txtCompanyName) Then

Set Conn = CurrentProject.Connection
Set rst = Nothing
rst.Open "ServiceHistory", Conn, adOpenKeyset, adLockOptimistic

rst.AddNew

rst!SrvSystemID = Forms!frmSystemInfo.SysSystemID
rst!SrvCompanyName = Forms!frmSystemInfo.SysCompanyName
rst!SrvSerialNumber = Forms!frmSystemInfo.SysSerialNumber
rst!SrvSystemModel = Forms!frmSystemInfo.SysSystemModel

rst.Update


rst.Save

rst.Close

Me.RecordSource = "qrySystemInfoandSrvHistory"

Else
Me.RecordSource = "qrySystemInfoandSrvHistory"
End If

End Sub

The form opens and all four fields are populated as wanted.
The problem is that all the text fields are then locked. I
tried removing the rst.Close, but that didn't work. I have
a feeling I still have a lock on the record, but don't know how
to get around it. Any ideas?

Thanks as always,

B