In code this is the key:  dbAttachSavePWD

When linking manually, click the save password box when you get to the list
of tables.

Delete all linked tables and re-link using one of the ideas above.
Problem should disappear.

==============================================
I use this procedure to re-create links to Oracle.
There is a local Access table (tblODBCTables) that contains the table names
and primary key fields I want to link to on the Server.
Note: the source table name needs the Schema User prefix which is in the
code. The linked table name usually omits this.

Public Function LinkOracleTables(strDSN As String, strSchema As Variant,
strSchemaPwd As Variant) As Boolean
On Error GoTo Err_LinkOracleTables

 Dim db As Database, rs As Recordset, tdfAccess As TableDef, qdf As
QueryDef
 Dim dbODBC As Database, strConnect As String, strSQL As String

 If strDSN = "" Then
   MsgBox "You must supply a DSN in order to link tables."
   Exit Sub
 Else
   strConnect = "ODBC;DSN=" & strDSN & ";UID=xyz" & ";PWD=abc;"
 End If

 SysCmd acSysCmdSetStatus, "Connecting to Oracle..."

 Call DeleteODBCTableNames

 Set db = CurrentDb
 Set rs = db.OpenRecordset("tblODBCTables")
 Set dbODBC = OpenDatabase("", False, False, strConnect)
 DoCmd.SetWarnings False

 Do While Not rs.EOF
   Set tdfAccess = db.CreateTableDef(rs![LinkTablename], dbAttachSavePWD)
   tdfAccess.Connect = dbODBC.Connect
    tdfAccess.SourceTableName = strSchema & "." & rs![LinkTablename]
   db.TableDefs.Append tdfAccess
   'run pseudo index queries here. If the table does not exist then this
gets skipped.
   strSQL = "CREATE INDEX " & rs![LinkTablename] & "Idx ON " &
rs![LinkTablename] & " (" & rs![IndexFields] & ");"
   DoCmd.RunSQL strSQL
TableNotInCollection:
   rs.MoveNext
 Loop

 LinkOracleTables = True

Exit_LinkOracleTables:
 On Error Resume Next
 DoCmd.SetWarnings True
 rs.Close
 Set rs = Nothing
 Set dbODBC = Nothing
 Set db = Nothing
 SysCmd acSysCmdClearStatus
 Exit Function

Err_LinkOracleTables:
 Select Case Err.Number
   Case 3151
     MsgBox ("There is an ODBC datasource problem." & vbCrLf & "Please
verify the DSN and database are spelled correctly." & vbCrLf & "Note: They
can be case sensitive.")
   Case 3265, 3011, 7874 'item not in collection - table does not exist, or
can't find object
       Resume TableNotInCollection
   Case Else
     MsgBox "Error # " & Err.Number & " was generated by " & Err.Source &
vbCrLf & Err.Description, , "LogOnCode - LinkOracleTables"
 End Select
 LinkOracleTables = False
 Resume Exit_LinkOracleTables

End Function

'This procedure deletes all linked ODBC table names in an mdb.
Public Sub DeleteODBCTableNames()
On Error GoTo Err_DeleteODBCTableNames

   Dim dbs As Database, tdf As TableDef, I As Integer
   Set dbs = CurrentDb
   For I = dbs.TableDefs.Count - 1 To 0 Step -1
     Set tdf = dbs.TableDefs(I)
     If (tdf.Attributes And dbAttachedODBC) Then
       dbs.TableDefs.Delete (tdf.Name)
     End If
   Next I

   dbs.Close
   Set dbs = Nothing

Exit_DeleteODBCTableNames:
   Exit Sub

Err_DeleteODBCTableNames:
   MsgBox ("Error # " & Str(Err.Number) & " was generated by " & Err.Source
& Chr(13) & Err.Description)
   Resume Exit_DeleteODBCTableNames

End Sub