tsearch2 in postgresql 8.3.1 - invalid byte sequence for encoding "UTF8": 0xc3

hi,

i have an issue with tseach2, i just installed postgresql 8.3.1 on windows
using UTF8 server encoding / client encoding and LOCALE Canada / French.

CREATE DATABASE mydbWITH OWNER = me ENCODING = 'UTF8';
CREATE TABLE product
(
  product_id       SERIAL         NOT NULL,
  name             VARCHAR(50)    NOT NULL,
  description      VARCHAR(1000)  NOT NULL,
  CONSTRAINT pk_product PRIMARY KEY (product_id)
);
ALTER TABLE product ADD COLUMN search_vector tsvector;
CREATE INDEX idx_search_vector ON product USING gist(search_vector);

UPDATE product SET search_vector = setweight(to_tsvector(name), 'A') ||
to_tsvector(description);

ERROR: invalid byte sequence for encoding "UTF8": 0xc3
SQL state: 22021
Hint: This error can also happen if the byte sequence does not match the
encoding expected by the server, which is controlled by "client_encoding".

any idea why it's happening?
pat