I think i found the solution for this.
There is 39 line in a file easy-contact-forms-appconfigdata.php:
DEFINE('EASYCONTACTFORMS__fileUploadDir', ABSPATH . 'wp-content/plugins/easycontact_templates' . $ds . EASYCONTACTFORMS__fileFolder);
so i created folder /wp-content/plugins/easycontact_templates/files
file uploads are working correctly now.
