COPY FROM STDIN fails inside Pl/pgSQL function or in PgAdmin , but ok in psql

Hi,

(Pg 8.0.3 on Windows XP SP2, client psql, ODBC and pgAdmin )

Summary: COPY FROM STDIN works on psql, but not inside a Pl/pgSQL
function, nor a pgAdmin SQL window, and not on a ODBC command...

I would appreciate if anybody could explain me why this doesn't work:

-- create table
CREATE TABLE temp_data (
xx float,
yy float,
ww float,
hh float) WITHOUT OIDS;

-- create function
CREATE OR REPLACE FUNCTION check_data(text) RETURNS integer AS $func$
BEGIN

EXECUTE 'COPY temp_data(xx,yy,ww,hh) FROM STDIN WITH DELIMITER ''|'';'
||'\n' || $1 || '\n\\.';

-- just to get something out
return length($1);
END;
$func$ LANGUAGE plpgsql;

and then:

select check_data('1.0|2.0|3.0|4.0');

It gives out:
ERROR: syntax error at or near "1.0" at character 60
QUERY: COPY temp_data(xx,yy,ww,hh) FROM STDIN WITH DELIMITER '|';
1.0|2.0|3.0|4.0
\.
CONTEXT: PL/pgSQL function "check_data" line 8 at execute statement

Actually, if I do the COPY within a pgAdmin SQL command prompt, it
also fails. For example, the following, alone, without any plpgsql -

COPY temp_data(xx,yy,ww,hh) FROM STDIN WITH DELIMITER '|';
1.0|2.0|3.0|4.0
\.
will fail.

If on the other hand, I execute these lines on a psql prompt, it works
just fine.

Any help will be appreciated.

Regards
Silvio