I took it upon myself to help out a buddy with his opencart site. I've managed e-commerce sites before but not with opencart as backend.
It was a fresh 2.3.0.2 installation with only products added. Nothing else was done yet.
I thought the first thing we should do before buying a theme, modules and setting everything up is to update opencart to the latest version first.
I followed the http://docs.opencart.com/upgrading/ tutorial. I made a backup of the DB (but not the files

After the copying was done, the website became unavailable. The error.log has a lot of errors :s
So to test something out, I made a new dir with a fresh v3 install, and it seems to work fine. So I assume either a theme or module is causing the errors ?
Also, in the subdir with a fresh v3, I imported the DB again, but his product/categories are not there. In fact, it doesn't seem to have imported anything. No products and no settings either.
Would appreciate some assistence in how to fix this.