ERROR: Invalid EUC_CN character sequence found (0x8000)

I met ERROR when I try to make a search using like 'Z%' with EUC_CN database. The next is the snapshot. Could any help me? Thanks.

palo=> \l
List of databases
Name | Owner | Encoding
-----------+----------+-----------
palo | palouser | EUC_CN

palo=> select * from sysuser where userid like 'Z%';
ERROR: Invalid EUC_CN character sequence found (0x8000)

[leon(at)test leon]$ psql -V
psql (PostgreSQL) 7.2.2
contains support for: readline, history, multibyte
Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
Portions Copyright (c) 1996, Regents of the University of California
Read the file COPYRIGHT or use the command \copyright to see the
usage and distribution terms.

B.R.
LEON
JUST DO IT! NOW!