Invalid EUC_TW character sequence found

Recently, I have installed the version 7.2.1 to my Redhat 6.1 server
with the following configure:

./configure --prefix=/usr/local/pgsql --enable-multibyte=EUC_TW
--with-perl --with-python --with-tcl --enable-odbc

After the installation, I have tried to restore some of my old databases
from version 7.0.2  but in vain owing to invalid character found.

Then I have tried to input some chinese character (big 5) directly,   It
gave me some errors as shown below from the pgAdmin II:

2002-06-25 17:20:13 - SQL (AccessControl): UPDATE "site" SET "cname" =
'­» ´ä ¦r' WHERE "siteid" = '001' AND "name" = 'this is HK' AND "cname"
= '­» ´ä'

2002-06-25 17:20:13 -
*******************************************************************
2002-06-25 17:20:13 - Error
2002-06-25 17:20:13 -
*******************************************************************
2002-06-25 17:20:13 - Error in pgAdmin II:frmSQLOutput.cmdSave_Click:
-2147467259 - ERROR:  Invalid EUC_TW character sequence found (0xa672)

If there is any compatibility issue between the old version and the new
one.

Best Regards
Gene Leung