I've been using the Qwilm theme, modified quite a bit in appearance. I announced my site, and the first time someone posted a comment, it caused a problem with displaying that page and its comment -- it just shows a very short white box. It also suppressed the sidebar, which is inserted in the code after the comments section. You can see this in action at http://www.mendocinofun.com/museums, and pretty much any other page shows what it should be like.
I don't expect specific help with this problem, but it tells me I better learn quickly how to debug. There's no outward indication of an error -- is there a log somewhere? Is there a way to see where the PHP code is breaking? Is there a debugger or anything like that? Or a way to trap errors like TRY/RECOVER or its equivalent so that it continues without dropping the rest of the page?
Is there a guide on debugging? I've programmed a lot, but not too much in PHP. Everything has just worked so nicely since I've been using WordPress, at least until I went live -- and I have my first couple of paying ads in the sidebar. Ouch!
In case anyone is familiar with Qwilm, I didn't change anything around where the comments are inserted, or anything in comments.php except the email address.
Thanks for any help at learning how to debug in this environment....