Checkout problem on my Subdomain

The checkout page shows error 404 page not found on my subdomain(sub.yoursite.com/checkout) and also the checkout template shows my main domain(yoursite.com) but the url is still in my subdomain(sub.yoursite.com/checkout)

site. http://member.igrowgolf.com/ please try to click checkout

Thanks!

http://wordpress.org/plugins/woocommerce/