Hehe, yeah, just for kicks. I am hyper-productive.
Okay, after several other investigation, seems like the error is related to the length of the message rather than content. It seems to break at around 1940 characters...weird...
2 2007-08-28 22:15
Topic: PunBB 1.3 bug (3 replies, posted in PunBB 1.2 troubleshooting)
You guys did a great job on PunBB by the way. And to show my appreciation, I will become the QA on 1.3 for you 
And yes, I found a bug today!
I got the generic 500 error today, and after commenting/uncommenting stuff out, I found out that the issue comes from this line:
'^((.|\n)*)$' => '<p>$1</p>', // wrap whole message in p tags
inside parser.php (Line 99)
It's called as part of the NEW_PARSE_MESSAGE(). It doesn't seem to fail on all post messages. I am not sure if certain characters break the regex, but I can tell you one of the messages that fail has: +, /, -, ? and the [url]BB code (plus the alphabets of course).
Any idea what is wrong?
Thanks!