Database Software

I have set up a UTF-8 database, on my english version of WinXP..

SELECT * FROM NLS_DATABASE_PARAMETERS;

.. shows this is correct - UTF8

I have set up NLS_LANG variable in windows, to be "American.America.UTF8"

Using SQL*Plus worksheet I can update a row in my database to contain chinese characters. I dont know what the chinese means, but I can copy and paste from another application, and the glyphs looks the same in the source and SQL*Plus worksheet.

I can then select the row ..

SELECT * FROM THETABLE WHERE THECOLUMN = '{CHINESECHARS}';

The correct row is returned, but the column is shown with just question marks, instead of the glyphs I expect.

(This also happens with the web application I am developing which also seems to return qurestion marks. (PHP not JSP))

Can anyone shed any light on this problem as I am completely stuck.