Displayed “Invalid entity model” error, While Exporting Products and Customers in Magento!
Its due to permission issue. Some time this error display in windows server.
Solution:
Open abstract class /app/code/core/Mage/ImportExport/Model/Export/Adapter/Abstract.php
and replace line number 60(Line number will change some time)
//$destination = tempnam(sys_get_temp_dir(), 'importexport_');
//Change above like as like BELOW:
$destination = tempnam(Mage::getBaseDir() . '/var/tmp/' , 'importexport_');
NOTE: Also, make sure “root/var/tmp/” folder have full permission.