Am 14.05.2010 um 15:44 schrieb Ahmad Essam:
\usepackage[helvetica]{quotchap}
It's not polyglossia, it's this command: it is going to use a 7-bit or 8-bit (OT1 or T1) encoded Helvetica font. Such a font cannot contain any Arabic so nothing gets printed.
Adapt quotchap that it uses fontspec supplied fonts! -- Greetings Pete A mathematician is a device for turning coffee into theorems. – Erdős Pál -------------------------------------------------- Subscriptions, Archive, and List information, etc.: http://tug.org/mailman/listinfo/xetex