Audit enabling problem

[shantanu125]

Hi buddies,
I am facing problem while enabling audit.

The steps I have followed are:
1.Create the audit trail views by connecting as sys and
running the script cataudit.sql.
2.grant audit permission by issuing command:
audit session by session whenever successful
3.setting audit_trail = true in file Initorcl.ora of \\orant\database

I have written a query to show audit informations. The query is:
SELECT SYS.DBA_AUDIT_SESSION.OS_USERNAME,
SYS.DBA_AUDIT_SESSION.USERNAME,
SYS.DBA_AUDIT_SESSION.TERMINAL,
SYS.DBA_AUDIT_SESSION.SESSIONID,
SYS.DBA_AUDIT_SESSION.TIMESTAMP,
SYS.DBA_AUDIT_SESSION.LOGOFF_TIME
FROM SYS.DBA_AUDIT_SESSION
ORDER BY SYS.DBA_AUDIT_SESSION.SESSIONID DESC ;

At our end when we run this query logging as administrator to database all information is displayed correctly.
But when we try to repeat whole procedure at client side the result is
'no rows found'. I have verified that all the steps have been followed
correctly at clients side.
What could be the possible reason....
Can anybody help...... :-X]