Yii2 Multi input framework on the same form

I'm using the widget widget along with yii2 and I'm having a commit-time error.

My scenario is as follows: In my catalog form the user can create the catalog , create as many catalog items as he wants. That is, I use in the catalog creation form the multi input widget to create multiple records of type catalog items

I'm having the following error:

Myformcode:

<?=$form->field($model,'mensagem2')->textInput(['maxlength'=>true])?><?php$models=Ponto_venda::find()->asArray()->all();$map=ArrayHelper::map($models,'id_ponto_v',function($model,$defaultValue){return$model['nome'].'-'.$model['descricao'];});?><divclass="row">
        <div class="col-lg-11">
            <?= $form->field($model, 'ponto_venda_id_ponto_v')->dropDownList($map) ?>
        </div>
        <div class="col-lg-1">
             <a class="btn btn-primary" href="index.php?r=ponto_venda%2Fcreate" role="button" style="margin-top:25px;"><span class="glyphicon glyphicon-plus"></span></a>
        </div>
    </div>
    <!-- Parte dos itens do catalogo -->
    <?php
        $item_models = Cerveja::find()->asArray()->all();
        $item_map = ArrayHelper::map($item_models, 'id_cerveja', function($item, $defaultValue) {return $item['nome'].' - '.$item['marca_id_marca'];}); 
    ?>      
    <br/>
    <?= $form->field($item, 'Item_catalogo')->widget(MultipleInput::className(), [
        'max' => 4,
        'columns' => [
            [
                'name'  => 'cerveja_id_cerveja',
                'type'  => 'dropDownList',
                'title' => 'Cerveja',
                'items' =>$item_map
            ],

            [
                'name'  => 'preco1',
                'enableError' => true,
                'title' => 'Preço1',
            ],
            [
                'name'  => 'preco2',
                'enableError' => true,
                'title' => 'Preço2',
            ],
            [
                'name'  => 'preco3',
                'enableError' => true,
                'title' => 'Preço3',
            ],
        ]
     ]);
    ?>
    <!-- -->

I can not understand why the error to commit the catalog items being that POST is apparently all respecting the integrity rules ... I'm new to the framework ... Thanks!