That is still V1
const uri_account_info = '1/generic/private/info';
const uri_new_address = '1/generic/bitcoin/address';
const uri_add_private_key = '1/generic/private/bitcoin/addpriv';
const uri_add_wallet_dat = '1/generic/bitcoin/wallet_add';
const uri_withdraw_coins = '1/generic/bitcoin/send_simple';
const uri_id_key = '1/generic/private/idkey';
const uri_trade_history = '1/BTC%s/private/trades';
const uri_wallet_history = '1/generic/private/wallet/history';
const uri_wallet_history_alt = '1/generic/wallet/history';
const uri_submit_order = '1/BTC%s/private/order/add';
const uri_get_orders = '1/generic/private/orders';
const uri_order_result = '1/generic/private/order/result';
const uri_cancel_order = '0/cancelOrder.php';
Those are V1 endpoints for the api.
https://github.com/pathaksa/MtGox-PHP-API-V2 and it does not support an order at market price, so just get the current price and set that as the order price.