I'm curious as to what SQL collation you have Dynamics GP setup on, as usually Arabic characters will have issues with the two collations that are technically supported with Microsoft Dynamics GP:
--DOCI (SQL_Latin1_General_CP1_CI_AS)
--Binary (Latin1_General_BIN)
I'm also curious on what version of Dynamics GP you're currently on as I want to say we had an issue back in GP 2013 that hampered the use of Arabic characters which was fixed in GP 2015.
I know from my own testing of GP and Arabic characters, which this would be about 2 years ago, the rich client works fine as long as the region/language and keyboard settings are set to Arabic/Saudi Arabia (for example), it’ll show Arabic characters correctly, even in reports I print to screen. If the keyboard language is English/U.S., it shows as gibberish.
That being said, on the Dynamics GP support side we don't see many cases with Arabic characters and Dynamics GP mainly because, as mentioned, the two collations we support for SQL/Dynamics GP don't work with Arabic characters for the most part, making it an un-supported environment, thus we're limited.
There may be some others out here on the forums that have more experience with Dynamics GP and Arabic characters that can help.
Thanks