Japanese Data(Names) Retrieval

Hi All,

I am facing a very strange problem,

I am firing the following query to my Oracle database:

SELECT DISTINCT a.SC_CONT_EMAIL 
FROM SCAT_CONTACT a, scat_customer b 
WHERE a.sc_customer_id=b.sc_customer_id 
AND a.SC_CONT_LAST_NAME = N'小島' 
AND b.sc_cust_password is not null

This query works fine for all the names in my database except for a few. 

These names are 
1) 三上 
2) \xA8焉扤扤村 
3) 河島  

Can somebody please guide me, what could be the possible cause for the query 
not working fine for the above mentioned names ?
Thanks a lot.

Regards
Ashutosh Sangle.