SQLSTATE[42S02]: Base table or view not found: 1146 Table 'llidiamabdd.employees' doesn't exist

You can hook custom 3rd party controls in the add and edit dialogs. Just hook the client-side event dataInit in colModel editoptions property using setColProperty and then associate the 3rd party control with the text-field.

For implementation details, please take a look at the PHP tab.
<?php
require_once '../../../tabs.php';
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
  <head>
    <title>jqGrid PHP Demo</title>
    <link rel="stylesheet" type="text/css" media="screen" href="../../../themes/redmond/jquery-ui-custom.css" />
    <link rel="stylesheet" type="text/css" media="screen" href="../../../themes/ui.jqgrid.css" />
    <link rel="stylesheet" type="text/css" media="screen" href="../../../themes/ui.multiselect.css" />
    <style type="text">
        html, body {
        margin: 0;            /* Remove body margin/padding */
        padding: 0;
        overflow: hidden;    /* Remove scroll bars on browser window */
        font-size: 75%;
        }
        .ui-datepicker {z-index:1200;}
    </style>
    <script src="../../../js/jquery.js" type="text/javascript"></script>
    <script src="../../../js/i18n/grid.locale-en.js" type="text/javascript"></script>
    <script type="text/javascript">
    $.jgrid.no_legacy_api = true;
    $.jgrid.useJSON = true;
    </script>
    <script src="../../../js/jquery.jqGrid.min.js" type="text/javascript"></script>
    <script src="../../../js/jquery-ui-custom.min.js" type="text/javascript"></script>
  </head>
  <body>
      <div>
          <?php include ("grid.php");?>
      </div>
      <br/>
      <?php tabs(array("grid.php"));?>
   </body>
</html>
grid.php.
<?php
require_once '../../../jq-config.php';
// include the jqGrid Class
require_once ABSPATH."php/jqGrid.php";
// include the driver class
require_once ABSPATH."php/jqGridPdo.php";
// Connection to the server
$conn = new PDO(DB_DSN,DB_USER,DB_PASSWORD);
// Tell the db that we use utf-8
$conn->query("SET NAMES utf8");

// Create the jqGrid instance
$grid = new jqGridRender($conn);
// Write the SQL Query
$grid->SelectCommand 'SELECT EmployeeID, FirstName, LastName, BirthDate FROM employees';
// Set the table to where you add the data
$grid->table 'employees';
// Set output format to json
$grid->dataType 'json';
// Let the grid create the model
$grid->setColModel();
// Set the url from where we obtain the data
$grid->setUrl('grid.php');
$grid->setColProperty('EmployeeID', array("editable"=>false));
$grid->setColProperty('BirthDate'
        array(
"formatter"=>"date",
            
"formatoptions"=>array("srcformat"=>"Y-m-d H:i:s""newformat"=>"Y-m-d"),
            
"editoptions"=>array("dataInit"=>
                
"js:function(elm){setTimeout(function(){
                    jQuery(elm).datepicker({dateFormat:'yy-mm-dd'});
                    jQuery('.ui-datepicker').css({'zIndex':'1200','font-size':'75%'});},100);}"
)
            ));
// Set some grid options
$grid->setGridOptions(array(
    
"rowNum"=>10,
    
"scrollrows"=>true,
    
"rowList"=>array(10,20,30),
    
"sortname"=>"EmployeeID"
));
$grid->navigatortrue;
$grid->setNavOptions('navigator', array("excel"=>false,"add"=>true,"edit"=>true,"del"=>false,"view"=>false"search"=>false));
// Close the dialog after editing
$grid->setNavOptions('edit',array("height"=>150,"dataheight"=>'auto'"closeAfterEdit"=>true));
$grid->setNavOptions('add',array("height"=>150,"dataheight"=>'auto',"closeAfterEdit"=>true));

// Enjoy
$grid->renderGrid('#grid','#pager',truenullnulltrue,true);
$conn null;
?>