have template that is linked to host. create web scenario with two steps on the template. try to delete one step - that fails :

Empty input parameter. [httpconf.php:226 ? CAPIObject->update() ? CAPIObject->__call() ? czbxrpc::call() ? czbxrpc::callAPI() ? call_user_func() ? CHttpTest->update() ? CHttpTestManager->persist() ? CHttpTestManager->inherit() ? CHttpTestManager->save() ? CHttpTestManager->update() ? CHttpTestManager->deleteStepsReal() ? CItem->delete() ? CZBXAPI::exception() in htdocs/trunk/api/classes/CItem.php:671]