Checkout error

Hello Friends,
Pardon me for bothering you here but i am a newbie at woocommerce. Last night, i had just finished my e-commerce site with woo commerce site using the “boutique shop theme” when i decided to try it out like a visitor, everything was going on fine till i got to the “checkout page” where i was hit with this error message at the foot of the page

Fatal error: Call to undefined method WC_Shipping::get_available_shipping_methods() in /home2/Username/public_html/wp-content/themes/boutique_shop/woocommerce/checkout/review-order.php on line 8

I enabled “create an account” but when i picked a username and password, it does not show the “register button” to proceed to the review and then finally “place order”.

I have no idea what that error means or why i am missing a “register” button. Please, can someone tell me what the problem could be and how to fix it.

Thanks in advance.