Consider the following code ...

Public Sub TableTypeRecordsets()

   Dim db As DAO.Database
   Dim rst1 As DAO.Recordset
   Dim rst2 As DAO.Recordset
   Dim rst3 As DAO.Recordset

   Set db = CurrentDb
   Set rst1 = db.OpenRecordset("tblTest", dbOpenTable)
   Debug.Print rst1.Type
   rst1.Close
   Set rst2 = db.OpenRecordset("tblTest")
   Debug.Print rst2.Type
   rst2.Close
   Set rst3 = db.OpenRecordset("SELECT * FROM tblTest")
   Debug.Print rst3.Type
   rst3.Close

End Sub

The first recordset, rst1, is, obviously enough, a table-type recordset,
because we opened it using the dbOpenTable argument. But what about rst2 and
rst3? Well, rst2 will be a table-type recordset if the table 'tblTest' is a
local table, or a dynaset-type recordset if the table is a linked table,
because those are the defaults that DAO uses if you don't specify the
recordset type. The third recordset, rst3, will be a dynaset-type recordset,
because that is the default when the source is a SQL statement or query
rather than a table name.

Look for references to either the Index property of the Seek method of
recordsets in your code, both of which require a table-type recordset. Don't
just assume that every reference to 'Index' in the code is a reference to
the Index property of a recordset, though, because there may be references
to the Index object, which is not directly relevant to this problem.

Take a look at the help topic for the OpenRecordset method, it explains the
different recordset types.