1.5.7 upgrade

Error upgrading 1.5.6 -> 1.5.7 Using file xenforo_1.5.7_759413274E_upgrade.zip URL: install/index.php?upgrade/run-deferred Error message: Fatal error: include() [<a href='function.include'>function.include</a>]: Cannot redeclare class xenforo_deferred_importmasterdata in...