to be able to post in arabic you should do the following

1-make sure your database collation is utf_unicode... ( having this collation is so important
if you want your website to support different languages other than english)

2- now you should edit your template index.php
locate this line

and change it to


now you have your template supporting different languages

3- go to fireboard languge folder and open english.php using notepad
save this file as encoding utf-8

try adding new post in arabic now and u should be fine!