Ok, thanks
I have tried debugging option on, and I did not see any errors on the page, even though that option is enabled. Nor could I find the server log file, maybe perhaps it is because we're using a sherd hosting account that uses Linux.
The only thing I have picked up on is that one of the categories under the actual quiz activity was as the others are assigned to the course itself. Also in the database, I see a lot of unknown host under the stamp column.