lost link to products from category listing

-- url of the page with the problem -- : www.hikashop.khotso.com.au/index.php/shop/categories
-- HikaShop version -- : 2.3.2
-- Joomla version -- : 3.3.3
-- PHP version -- : 5.3.28
-- Browser(s) name and version -- : Mozilla/5.0 (Windows NT 6.0; rv:31.0) Gecko/20100101 Firefox/31.0
-- Error-message(debug-mod must be tuned on) -- : Error_message no error message until selecting the "category"
Not Found
The requested URL /anodising was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

when trying to get product listing from the individual categories the error message comes up Not Found [as above ]

really would appreciate if I could get comment(s) on where I must investigate to solve this as I am at standstill

That has fixed the problem..... I have removed text in the canonical url and that has taken care of the problem , thank you. it was not a URL in the true sence of URL and hence, this problem.showed

Sorry to ask but in what format must this URL be in to be effective...... as obviously I would like diferent categories to be identified individually
Additionally how does it link with individual products (do I need to repeat this manually with each product?
In the category URL do i need to add the site name???

not very familiar with this SEO area so your help is really appreciated