select duplicados

Hola tengo un archivo php que construlle un formulario:

if (is_array($incidencias)) 
/*  echo '<div class="modal-content">';
 
 */     
 
    echo '<div id="modalheader" class="modal-header">'; 
    echo    '<button type="button" class="close" data-dismiss="modal">&times;</button>';
    echo    '<h4 class="modal-title">Seleccione Contrat88888o</h4>';
    echo  '</div>';
 
{   
    echo '<div id="modalbody" class="modal-body">';   
    echo    '<form  id="formcontract" action="mira.php"  class="form-horizontal">';
    echo    '<div id="select" class="form-group">';
    echo        '<label class="col-sm-3 control-label" for="formGroup" id="contract">Contratos</label>';
 
    echo        '<div class="input-group col-sm-7">';
    echo        '<span class="input-group-addon"><span class="glyphicon glyphicon-list-alt"></span></span>';    
    echo        '<select  name="contrato" class="selectboxit">';
    echo '<option selected="disabled">Selecciona un Contrato</option>';
    foreach($incidencias as $cust) 
    { 
            echo '<option value="'.$cust->Num_distribucion.'-'.$cust->Num_dist_venta.'-'.$cust->Num_linea_operacion.'-'.$cust->Num_operacion.'">'.$cust->Num_contrato.' '.$cust->Cdad_disponible.'Kg de '.$cust->NombreProducto.'</option>';
 
    }
 
            echo '</select>';
    echo '</div>';
    echo '</div>';
 
    echo '<div class="col-xs-4">';
    /* echo '<input type="text" class="form-control"  size="5" name="cupo" id="cupo" disabled/>'; */
 
    echo '</div>';
    echo '</div>';
    echo '</div>';
    echo '<div class="col-sm-12">&nbsp;</div>';
    echo '<div class="col-sm-12">&nbsp;</div>';
    echo '<div class="col-sm-12">&nbsp;</div>';
 
    /* echo  "Toneladas de "; */
 
echo '<div class="modal-header">
 
        <h4 class="modal-title">Autorización de Matrículas</h4>
    </div>
<div class="col-sm-2">&nbsp;</div>
<div class="col-sm-3">&nbsp;</div>
 
 <div class="modal-body">
 
                    <div class="form-group">
                            <label class="col-sm-3 control-label" for="formGroup">Tractora</label>
                              <div class="input-group col-sm-5">
                                <span class="input-group-addon"><span class="fa fa-keyboard-o"></span></span>
                              <input class="form-control" type="text" name="matricula" id="formGroup" placeholder="AAA1234">
 
                            </div>
                        </div>  
<div class="col-sm-12">&nbsp;</div>
<div class="col-sm-12">&nbsp;</div>
                    <div class="form-group">
                            <label class="col-sm-3 control-label" for="formGroup">Remolque</label>
                              <div class="input-group col-sm-5">
                                <span class="input-group-addon"><span class="fa fa-keyboard-o"></span></span>
                              <input class="form-control" type="text" name="matricular" id="formGroup" placeholder="AAA1234">
 
                            </div>
                          </div>    
<div class="col-sm-12">&nbsp;</div>
<div class="col-sm-12">&nbsp;</div>                     
                    <div class="form-group">
                            <label class="col-sm-3 control-label" for="formGroup">N.I.F-N.I.E</label>
                              <div class="input-group col-sm-5">
                            <span class="input-group-addon"><span class="fa fa-credit-card"></span></span>
                              <input class="form-control" type="text" name="dni" id="formGroup" placeholder="DNI o PASAPORTE">
                                </div>
                        </div>
<div class="col-sm-12">&nbsp;</div>
<div class="col-sm-12">&nbsp;</div>                                 
                    <div class="form-group">
                            <label class="col-sm-3 control-label" for="formGroup">Conductor</label>
                              <div class="input-group col-sm-5">
                            <span class="input-group-addon"><span class="entypo-user"></span></span>
                              <input class="form-control" type="text" name="xofer" id="formGroup" placeholder="Nombre y Apellido">
                                </div>
                        </div>
<div class="col-sm-12">&nbsp;</div>
<div class="col-sm-12">&nbsp;</div>
    <div class="form-group">
                            <label class="col-sm-3 control-label" for="formGroup">P.M.A</label>
                              <div class="input-group col-sm-5">
                            <span class="input-group-addon"><span class="entypo-download"></span></span>
                              <select name="pma" id="formGroup" class="selectboxit">
                              <option>40.800</option>
                              <option>41.000</option>
                              <option>44.000</option>
                              </select>
                            </div>
        <div class="col-sm-12">&nbsp;</div>
    <div class="col-sm-12">&nbsp;</div>
    <div class="modal-footer">
                        <input class="btn btn-success" id="enviar" type="submit" value="Enviar" />
                        </div>                        
    </div>
 
                </form>';
 
}

Si lo lanzo en el navegador queda de muerte pero al llamarlo en una ventana modal se me deuplican los select lo llamo asi:

div class="modal fade" id="ventana" tabindex="-1" role="dialog" aria-labelledby="ModalLabel" aria-hidden="true">
              <div class="modal-dialog modal-lg">
                <div class="modal-content">
 
                  <div class="modal-header">
 
                  </div>
 
                  <div class="modal-body">
 
                     <?php include("contratos8.php");?>
                  </div>
´´´
Podeis ver una muestra aqui:
http://postimg.org/image/rxkpglemn/
 
Gracias