Hikashop Error!

-- HikaShop version -- : 2.3.0
-- Joomla version -- : 3.2

I've been editing categories and changed the name of the ROOT category but immediately after saving I receive the message:

SQL=SELECT category_id FROM ******_hikashop_category WHERE category_parent_id= AND category_type='product' LIMIT 1

I'm now completely locked out of most of hikashop

I can access some of the shop such as customer information but if I try to access categories, products or the main configuration page I'm hit with the above error message and returned to the Joomla control panel.

Any advice on how I can fix this please? I really don't want to have to start again from scratch

I can't take a screenshot since the entire cart crashed and whenever I tried to access it, it just gave the SQL Error. My only option was to reinstall the database (luckily its on a test server at the moment).