404 error and more

So I’m trying to setup my online store and I keep getting an error upon checkout. Here is my systems status. I have no clue as to how to fix this. Any help would be greatly appreciated.

### WordPress Environment ###

Home URL: http://superiorriflesystems.com
Site URL: http://superiorriflesystems.com
WC Version: 2.6.4
Log Directory Writable: ✔
WP Version: 4.6.1
WP Multisite: –
WP Memory Limit: ❌ 40 MB - We recommend setting memory to at least 64MB. See: Increasing memory allocated to PHP
WP Debug Mode: –
WP Cron: ✔
Language: en_US

### Server Environment ###

Server Info: Apache
PHP Version: ❌ 5.4.45 - We recommend a minimum PHP version of 5.6. See: How to update your PHP version
PHP Post Max Size: 64 MB
PHP Time Limit: 30
PHP Max Input Vars: 1000
cURL Version: 7.19.7
NSS/3.21 Basic ECC

SUHOSIN Installed: –
MySQL Version: ❌ 5.5.48 - We recommend a minimum MySQL version of 5.6. See: WordPress Requirements
Max Upload Size: 64 MB
Default Timezone is UTC: ✔
fsockopen/cURL: ✔
SoapClient: ✔
DOMDocument: ✔
GZip: ✔
Multibyte String: ✔
Remote Post: ✔
Remote Get: ✔

### Database ###

WC Database Version: 2.6.4
: 
woocommerce_sessions: ✔
woocommerce_api_keys: ✔
woocommerce_attribute_taxonomies: ✔
woocommerce_downloadable_product_permissions: ✔
woocommerce_order_items: ✔
woocommerce_order_itemmeta: ✔
woocommerce_tax_rates: ✔
woocommerce_tax_rate_locations: ✔
woocommerce_shipping_zones: ✔
woocommerce_shipping_zone_locations: ✔
woocommerce_shipping_zone_methods: ✔
woocommerce_payment_tokens: ✔
woocommerce_payment_tokenmeta: ✔
MaxMind GeoIP Database: ✔

### Active Plugins (20) ###

Redux Framework: by Team Redux – 3.6.1
LayerSlider WP: by Kreatura Media – 5.6.9
Ultimate Addons for Visual Composer: by Brainstorm Force – 3.8.0
Advanced Custom Fields: by Elliot Condon – 4.4.8
Advanced Sidebar Menu: by Mat Lipe – 6.1.0
All In One SEO Pack: by Michael Torbert – 2.3.9.2
Black Studio TinyMCE Widget: by Black Studio – 2.2.11
Captiva Toolkit: by Colm Troy – 1.2.4
Contact Form 7: by Takayuki Miyoshi – 4.5
Easy Google Fonts: by Titanium Themes – 1.4.1
WPBakery Visual Composer: by Michael M - WPBakery.com – 4.12.1
Regenerate Thumbnails: by Alex Mills (Viper007Bond) – 2.2.6
SeedProd Coming Soon Pro: by SeedProd – 4.5.4
UPS WooCommerce Shipping: by WooForce – 2.9.9
WooCommerce Quantity Increment: by Automattic
WooThemes – 1.1.0

WooCommerce: by WooThemes – 2.6.4
WooSidebars: by WooThemes – 1.4.3
YITH WooCommerce Ajax Product Filter: by YITHEMES – 3.0.9
YITH WooCommerce Ajax Search: by YITHEMES – 1.4.0
YITH WooCommerce Wishlist: by YITHEMES – 2.0.16

### Settings ###

Force SSL: ✔
Currency: USD ($)
Currency Position: left
Thousand Separator: ,
Decimal Separator: .
Number of Decimals: 2

### API ###

API Enabled: ✔

### WC Pages ###

Shop Base: #530 - /shop/
Cart: #531 - /cart/
Checkout: #532 - /checkout/
My Account: #533 - /my-account/

### Taxonomies ###

Product Types: external (external)
grouped (grouped)
simple (simple)
variable (variable)

### Theme ###

Name: Captiva
Version: 1.9.4
Author URL: http://www.commercegurus.com
Child Theme: ❌ – If you're modifying WooCommerce on a parent theme you didn't build personally
then we recommend using a child theme. See: How to create a child theme

WooCommerce Support: ✔

### Templates ###

Overrides: captiva/woocommerce/archive-product.php
captiva/woocommerce/checkout/form-checkout.php
captiva/woocommerce/checkout/review-order.php
captiva/woocommerce/content-product.php
captiva/woocommerce/content-product_cat.php
captiva/woocommerce/content-single-product.php
captiva/woocommerce/loop/loop-end.php
captiva/woocommerce/loop/loop-start.php
captiva/woocommerce/loop/orderby.php
captiva/woocommerce/loop/pagination.php
captiva/woocommerce/loop/result-count.php
captiva/woocommerce/loop/sale-flash.php
captiva/woocommerce/single-product/meta.php
captiva/woocommerce/single-product/price.php
captiva/woocommerce/single-product/product-image.php
captiva/woocommerce/single-product/related.php
captiva/woocommerce/single-product/sale-flash.php
captiva/woocommerce/single-product/share.php
captiva/woocommerce/single-product/short-description.php
captiva/woocommerce/single-product/tabs/tabs.php
captiva/woocommerce/single-product/title.php
captiva/woocommerce/single-product/up-sells.php
captiva/woocommerce/single-product.php