After downgrade, WebHelp output displays as blank

I recently had to temporarily use a newer version of the technical communications suite because of a computer crash, after which I had to go back to the older version -- the company I work at had a license to the older version.

Because I was working on RoboHelp 11, I couldn't open my projects when I was back to RH 10. I used the instructions in this post: Downgrade a RoboHelp Project | WvanWeelden.eu, and was able to open the project and make some changes, but when I generate to WebHelp and try to preview locally, I get a blank page on my browser. The only thing I see is a border between the supposed TOC and content, however there is nothing there. I tried to delete the CPD file, and to empty the SSL > WebHelp folder and re-generate, and I wasn't successful.

I wasn't encountering any problems with this project before the downgrade, so I suppose that is the cause, however I'm not sure what to do, and whether this means that the output won't display live as well as locally.