Most likely your page is erroring out due to a script issue but error reporting is disabled. I would recommend temporarily turning error reporting on via the .htaccess. You can do that by creating a file called ".htaccess" with the following content...
Code:
php_flag display_startup_errors on
php_flag display_errors on
php_flag html_errors on
php_flag ignore_repeated_errors off
php_flag ignore_repeated_source off
php_flag report_memleaks on
php_flag track_errors on
php_value docref_root 0
php_value docref_ext 0
php_value error_reporting 999999999
php_value log_errors_max_len 0
Upload that file to your forum root, attempt to post and post the error you (should) get here