Fatal error: Class 'Helper_Data' not found in app\Mage.php
Fatal error: Class 'Mage_Parcelamento_Helper_Data' not found in
C:\wamp64\www\magento\app\Mage.php on line 547
Warning: include(Mage\Parcelamento\Helper\Data.php): failed to open stream: No such file or directory in lib\Varien\Autoload.php on line 94
I did what you said, but it's still with the same error.