Magento Fatal error: Unsupported operand types

Fatal error when do exporting products in Magento:

Fatal error: Unsupported operand types in D:\_$projects\23. MIREI\23.1 mirei.vn\Magento\app\code\core\Mage\ImportExport\Model\Export\Entity\Product.php on line 875

In order to fix this issue:

• 1. Open the file Product.php in the folder Magento\app\code\core\Mage\ImportExport\Model\Export\Entity\
• 2. Find the line

  $dataRow += $stockItemRows[$productId];

  In Magento Community 1.9.1.1, it should be line #875

• 3. Replace with:

  $dataRow = array_merge($dataRow,$stockItemRows[$productId]);
  

The new code should be:

//$dataRow += $stockItemRows[$productId];
$dataRow = array_merge($dataRow,$stockItemRows[$productId]);