Current Recordset Does Not Support Updating

i'm getting this message when i try and change a record in a table via a recordset... but i am using CursorType = adLockOptimistic which i thought let you make changes to the table

here is my code so far

Dim rst As ADODB.Recordset
Set rst = New ADODB.Recordset
rst.CursorLocation = adUseServer
rst.CursorType = adLockOptimistic
rst.Open "TBL_TmpSubmission", CurrentProject.Connection

If rst.RecordCount > 0 Then
Do While Not rst.EOF
MsgBox rst!PropertyType, vbOKOnly, "debug"
If DCount("[PropertyType]", "[TBL_PropertyType]", "PropertyType = '" & rst!PropertyType & "'") <> 1 Then
rst!PropertyType = DLookup("[PropertyType]", "[TBL_PropertyType]", "IDPropertyType = " & rst!PropertyType)
MsgBox "property changed", vbOKOnly, "debug"
Else
MsgBox "good property", vbOKOnly, "debug"
End If
rst.MoveNext
Loop
End If

rst.Close


am i using the wrong combination or cursor and lock type here? reading the help it seems i should be able to make changes to the table.