mssql_execute falla con rangos de fecha :(

[harvestmoon]

pues he probado de muchas maneras y tengo el mismo error

Warning: mssql_execute() [function.mssql-execute]: stored procedure execution failed in

lo he dejado todo de esta manera

$dblink = mssql_connect("cyaserversan","sa","sqlcyasa");
$success = mssql_select_db("CyA30G",$dblink);
$ini='20090525';
$fin='20091027';
//$result = mssql_query("sprptSabanaDGI 20090525, 20091027");
$stmt=mssql_init('sprptSabanaDGI',$dblink);
$ini='20090525';
$fin='20091027';
mssql_bind($stmt, "@FechaIni", $ini, SQLVARCHAR, false, false, 20);
mssql_bind($stmt, "@FechaFin", $fin, SQLVARCHAR, false, false, 20);
$result=mssql_execute($stmt);
while($row=mssql_fetch_array($result)){
$valor1="1";


echo "<tr>\n";
echo "<td bgcolor='#FFFFFF'>$row[ProtAno]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[NumeroEscritura]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[FechaEscritura]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[Acreditado]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[ISM]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[IMza]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[ILote]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[ICasa]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[IUnidadPrivativa]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[IFracc]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[ILocalidad]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CopiaSimple]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[Predial]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CedulaCatastral]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[Avaluo]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[Agua]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CertificadoGravamen]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[TablaAmortizacion]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CartaContratacionSeguro]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[LiquidacionCredito]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CartaComplementoPoder]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[InstruccionFiduciaria]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[ActaMatrimonio]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CartaNaturalizacion]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CooperacionMunicipal]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CooperacionEstatal]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[NoAdeudoPredial]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[FolioDoc]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CartaNotarialInfonavit]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[InstruccionComiteTecnico]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CartInicioTramite]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CartaCesionCredito]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[SolicitudInscripcionCredito]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[AvisoRetencion]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CartaEntidadFinanciera]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[DisposicionesCrediticias]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[DescripcionVivienda]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[TablaIndiviso]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[ConstanciaCredito]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CartaInstruccionIrrevocable]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[CaratulaCreditoHipotecarioCAT]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[ReciboPagoCoopMunicipal]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[AnexoA]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[AnexoB]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[AnexoC]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[ActaSinValor]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[AvisoCatrastral]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[RegimenEscritura]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[RegimenNotaria]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[FolioRegimen]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[Folio]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[Credito]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[Hipotecaria]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[Inmobiliaria]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[NumCreditoInfonavit]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[NumCreditoHipotecario]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[NumSeguroSocial]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[AbogadoNombre]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[Fondo]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[ISAI]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[Derechos]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[Departamento]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[FechaDepartamento]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[RPPBoletaIngreso]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[FechaBoleta]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[GuiaANEC]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[FechaEntrega2Testimonio]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[EntregadoA]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[FirmaDGI]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[DGIPago]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[DGICierre]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[Num]</td>\n";
echo "<td bgcolor='#FFFFFF'>$row[StatusEsc]</td>\n";
echo "</tr>\n";
}
echo "</table>\n";

por favor ayudenme gracias
:)