Sorry for a late reply - I've entered your link today and noticed you have complete paragraphs of Chinese chars posted.
Did you solve the problem somehow?
Anyway, for the future... if such a problem appears, you need to determine the nature of it i.e. understand what kind of code is causing it. Because if it works on our server and doesn't work on yours, and we have almost the same configuration, it means the problem could be somewhere on your end.
In the case of your problem, you could debug it that way:
- edit bb_func_pthread.php
- look up for $postText
- put this code after this or that line following from top to bottom of the code:
Then post something and watch after which function the $postText value will lose its original value.
I suppose this will happen after textFilter function, but I have no ideas what exactly in this function will cause the trouble, so you will need to debug this function as well (bb_func_txt.php).