VB6 Recordset Update Method Fails On SQL 2005 Server

Hi to all....

I'm new on this forum, but, I'm a experienced programmer.
I wanna solve this problem (if you can helpme....), recently, I'm trying to migrate an old SQL 7 to the new SQL 2005 server enterprise edition, I have no problem to import the data, users, stored procedures, etc. and all work fine, I can connect troght ODBC from the others computers, including some older pentium 1 mmx 200 mhz. with WIN98 (yes!).

My problem is an legacy VB6 application that work (well fine) with SQL7 server, but, when i change the odbc of the desktops systems to the new 2005 SQL server and run this legacy application hi recibe this error:
(english translation from spanish language)

[ODBC SQL Server Driver][SQL Server] The table to be modified is not included on this cursor or these can't be modified throught this cursor.

I have look on the source code of the legacy application, and someone of the segment's that causes error is:

------------------------------------------------------------------------


Public Function ConsultaCamara(sRutOP As String, _
sRut1 As String, _
strConsulta As String, _
Tipo As String, _
chk As CheckBox, _
Timer1 As Timer, _
LbAviso As Label) As Long
'----------------------------
Dim rsCACH, rsCACH_upd0, rsCACH_upd1, rsCACH_upd2 As ADODB.Recordset
Dim CmCACH As ADODB.Command
Dim lPendiente As Boolean
Dim lActivo As Boolean
Dim strSQL1, strSQL_upd0, strSQL_upd1, strSQL_upd2 As String
Dim StrWHE As String
Dim DameTiempo As Integer
Dim snombre As String
Dim sMsgEstado As String
Dim sAviso_Inicial As String
Dim cNum As String
Dim cDig As String
...
...
...
'Defino el string de consulta
strSQL1 = " SELECT RUTOPERADOR, " & _
" IDCAMARA, " & _
" RUTCONSULTADO, " & _
" ESTADO, " & _
" CANCON, " & _
" CADENACONSULTA, " & _
" FINGRESO, " & _
" FULCONSINT, " & _
" ULTRUTOP " & _
" FROM BOLETIN " & _
" WHERE RUTCONSULTADO = '" & sRut1 & "'" & _
" AND (ESTADO = 'PE' OR ESTADO = 'AC' )"

Set rsCACH = CreateObject("ADODB.Recordset")
rsCACH.ActiveConnection = cn
rsCACH.CursorType = adOpenKeyset
rsCACH.LockType = adLockOptimistic
rsCACH.Open strSQL1
If rsCACH.EOF Then 'No hay registro antiguo o en consulta, creo uno para consultar
sMsgEstado = "NO Existen datos ES REGISTRO NUEVO" & vbCr
rsCACH.AddNew
ConsultaCamara = GeneraID()
rsCACH.Fields("IDCAMARA") = ConsultaCamara
rsCACH.Fields("RUTOPERADOR") = sRutOP
rsCACH.Fields("RUTCONSULTADO") = sRut1
rsCACH.Fields("ESTADO") = "PE"
rsCACH.Fields("CANCON") = 1
rsCACH.Fields("CADENACONSULTA") = strConsulta
rsCACH.Fields("FINGRESO") = GetDateTime() 'Format(Date, "Short Date")
rsCACH.Fields("FULCONSINT") = GetDateTime() 'Format(Date, "Short Date")
rsCACH.Fields("ULTRUTOP") = sRutOP
rsCACH.Update <----- here's launches the error
...
...
...

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As you see, I'm not english spokeman, I hope that you understand me.

Thanks and best regards.