In OpenCart v. 2.0.0 in /admin when I receive an order I should be able to change status of the order to let the customer know what is going on with her purchase. This functionality is in 'History' tab. Unfortunately I can't change or modify any orders. When I change the status and try to save it Openart gives me an error:
SyntaxError: JSON.parse: unexpected end of data at line 1 column 1 of the JSON data OK
It happens even on clean install. Everything is set up correctly - the domain name is OK, the shop is not in maintenance mode, there is no password in .htaccess file (BTW even removing it doesn't help).
It looks like in the screenshot attached.
The one solution is to install the newest version of OpenCart which is in the moment I'm writing this post 2.0.1.1. It's probably the best idea.
My problem is that I have made quite a lot of modifications and that would be very difficult for me. Making my changes I didn't use vqmod which probably I should use (but nobody is perfect - isn't she?). Or maybe you don't want to go into upgrade for a different reason?
Now, how to resolve this problem without actually changing the software itself?