I need help using ODBC

Below is some code that I have pieced together from help files, forums and out my backside. I have never used ODBC/DAO and therefore have no understanding of them whatsoever. When I run this code I get:

Run-time error '3027':
Can't update. Database or object is read-only.

The program is running on a windows 9x and is trying to save its data to a file on an AS/400.

What am I doing wrong, is this mess even close to right. Any comments or help would greatly be appriciated. Thanx

Option Explicit
Dim db As DAO.Database, rs As DAO.Recordset, ws As DAO.Workspace

Function AddToDatabase(SendEvent As String)
'Open the custcdt table

****************************************************
********************ERROR OCCURS HERE***************
***
Set rs = db.OpenRecordset("SELECT * FROM EPA", dbOpenDynaset)
***
********************ERROR OCCURS HERE***************
****************************************************

With rs
'Set it to Add mode
.AddNew
'Enter the field values
Select Case SendEvent
Case "EPA"
.Fields("EBLOWER").Value = lbl40538.Caption 'East Blower Damper Position
.Fields("WBLOWER").Value = lbl40537.Caption 'West Blower Damper Position
.Fields("AFCEPLN").Value = lbl40539.Caption 'A fce Plenum Damper Position
.Fields("BFCEPLN").Value = lbl40540.Caption 'B fce Plenum Damper Position
.Fields("AFCEH2O").Value = lbl40569.Caption 'A fce Water Cooled Damper Position
.Fields("BFCEH2O").Value = lbl40570.Caption 'B fce Water Cooled Damper Position
.Fields("FCEBLIN").Value = lbl40571.Caption 'fce Blower Inlet Damper Position
.Fields("FCEBLOUT").Value = lbl40572.Caption 'fce Blower Outlet Damper Position
.Fields("FCEBLCUR").Value = lbl40573.Caption 'fce Blower Current
.Fields("FCEE1000").Value = lbl40574.Caption 'fce East 1000 HP Blower Current
.Fields("FCEW1000").Value = lbl40575.Caption 'fce West 1000 HP Blower Current
.Fields("EPADATE").Value = Date 'Date of data saved.
.Fields("EPATIME").Value = Time 'Time of data saved.
Case "ChgA"
.Fields("CHGASTR").Value = lblStartA.Caption 'Start Time of Charge fce A
.Fields("CHGAEND").Value = lblEndA.Caption 'End Time of Charge fce A
.Fields("CHGASUM").Value = lblSumA.Caption 'Sum Time of Charge fce A
.Fields("EPADATE").Value = Date 'Date of data saved.
.Fields("EPATIME").Value = Time 'Time of data saved.
Case "ChgB"
.Fields("CHGBSTR").Value = lblStartB.Caption 'Start Time of Charge fce B
.Fields("CHGBEND").Value = lblEndB.Caption 'End Time of Charge fce B
.Fields("CHGBSUM").Value = lblSumB.Caption 'Sum Time of Charge fce B
.Fields("EPADATE").Value = Date 'Date of data saved.
.Fields("EPATIME").Value = Time 'Time of data saved.
End Select
'Update it
.Update
'Close it
.Close
End With

End Function

Private Sub Form_Load()
Set ws = DBEngine.CreateWorkspace("", "", "", dbUseODBC)
Set db = ws.OpenConnection("", , , "ODBC;DSN=EPA;uid=;pwd=;")
' Set db = OpenDatabase("", , , "ODBC;DSN=TestODBC;uid=;pwd=;")
End Sub

Private Sub txt40650_Change()
Call AddToDatabase("ChgA")
End Sub

Private Sub txt40655_Change()
Call AddToDatabase("ChgB")
End Sub