Arabic characters displayed as ?????

Hi,

I did an full database export of 8.0.6.0 database and imported in 10.2.0.4 (below 10g NLS Setting). All the arabic characters in 10g are shown as '???',but when i type and save arabic characters, they are displayed properly. Where could be the problem. Please advice

8.0.6 win 2003 server (32 bit ) NLS Setting

PARAMETER                                  VALUE
NLS_LANGUAGE                          AMERICAN
NLS_TERRITORY,                         AMERICA
NLS_CURRENCY,                            $
NLS_ISO_CURRENCY,                 AMERICA
NLS_NUMERIC_CHARACTERS,       .,
NLS_CHARACTERSET,               AR8MSWIN1256
NLS_CALENDAR,                        GREGORIAN
NLS_DATE_FORMAT,                  DD-MON-YY
NLS_DATE_LANGUAGE,              AMERICAN
NLS_SORT,                                    BINARY
NLS_NCHAR_CHARACTERSET,  AR8MSWIN1256
NLS_RDBMS_VERSION,                   8.0.6.0.0

10.2.0.4 win 2008 server (64 bit) NLS Settings

SQL> select * from nls_database_parameters;