I did changed my dbfDefault but still the problem exist.
Thanks for posting the shapefile. The shapefile is ANSI, and the Language ID in the file is indicating ANSI. I'll have to refer this issue to another team, and I'll post back here with any information I can.
The dbfDefault setting will definately not make any difference to the upload or display in the browser - its only going to affect viewing the shapefile in ArcGIS Desktop on your system (the Silverlight runtime does not have access to your system registry to read this for security reasons).
I was trying to find out any other ways around this issue - After doing some more research, I'm not sure that the windows arabic codepage can be encoded into the ANSI dbf file structure (there is not enough space available in the file structure to indicate the higher codepages). According to KB article 21106, you can have UTF-8 unicode shapefiles, so they would be able to store arabic characters correctly and it's possible the upload would work then; however, I cannot find out how to create a file like this, so I'm afraid I have no solution for this at the moment and I'll have to post back when I get some more information.
Most of my shapefile's attribute table are in arabic font and on the pop.ups, txt are appeared in different characters which cant be read...i really appreciate for any help on this matter...thanks