Hi everybody
I am in a local server using Xampp in windows7.
I need Entity API which is required for all components of drupal commerce modules. When i try to create a view of my products, and then configure all the fields, i have this message error in a javascript box dialog:

Une erreur HTTP AJAX s'est produite. (a error HTTP AJAX has occured)
Code de statut HTTP : 500 (Status code)
Informations de débogage ci-dessous. (debug infos below)
Chemin : /drupal/fr/admin/structure/views/view/services/preview/page/ajax
StatusText: Service unavailable (with message)
ResponseText : EntityMetadataWrapperException : Unknown data property commerce_product. dans EntityStructureWrapper->getPropertyInfo() (ligne 339 dans C:\xampp\htdocs\drupal\sites\all\modules\entity\includes\entity.wrapper.inc)

And when i try to load the page of the views, i have nearly the same message, in a blank page:

EntityMetadataWrapperException : Unknown data property commerce_product. dans EntityStructureWrapper->getPropertyInfo() (ligne 339 dans C:\xampp\htdocs\drupal\sites\all\modules\entity\includes\entity.wrapper.inc)

Here is the code of the function line 333 of the .inc file.

public function getPropertyInfo($name = NULL) {
    $this->spotInfo();
    if (!isset($name)) {
      return $this->propertyInfo['properties'];
    }
    if (!isset($this->propertyInfo['properties'][$name])) {
      throw new EntityMetadataWrapperException('Unknown data property ' . check_plain($name) . '.');
    }
    return $this->propertyInfo['properties'][$name] + $this->info['property defaults'] + $this->propertyInfoDefaults;
	}

Can someone help me to display the view of the products normally? Thanks.