PHP: $this->api->ban->isOp();//iam not sure if its the one above or below this !$this->ban->isOp(); I dont know wich of the two is it iam on holliday and i cant remember it! What is it on the new api?
$player->isOp(). Also, keep in mind that, in old plugins, $this->api refers to the $this->api = $api; line you wrote at the front, and $this->ban has obviously been never defined.