Tim Hunt

That is the right question to ask.

There is no clear answer. It requires thought.

Another alternative is to install ForumNG, and use the 'Study advice' forum type.

Yes. It should be OK to leave out those folders.

I still cannot see anything obviously wrong. I can only suggest that you poke around with Firebug (or a similar tool in another browser) to try to work out what is going on. In the net tab, are there any 404 errors. Can you see your JavaScript in the Script tab? If you put in a breakpoint (in the HTML of the page) can you step through and see exactly where it is failing?

Using LIKE here is wrong.

You should be using the $DB->sql_compare_text function, which generates the right SQL for this case for each database.