Sorry to be slow to answer.
I think mod_security is probably the most likely explanation. – the bane of every web developers life!
Can you ask your host to whitelist the forum admin calls? We have usually found them sympathetic.

Problem solved! Thanks, I’ll remember that Java console from now on!

Oh great news. I believe most of the main browsers now have some level of development tools available for them which has made tracking down problems like this much easier of course. And the CSS tools that allow you to inspect the CSS being applied to individual elements and change them in real time to see the result are just a fantastic aid to development.

Hi a really simple question, I hope?! – Where is the setting to stop asking math questions when a new user wants to post?

It’s a permission so just turn On the permission to bypass the math question on the appropriate permission set(s)