Text search, ERROR: invalid byte sequence for encoding "UTF8": 0xe9640a

I downloaded the hunspell en_GB from

http://wiki.services.openoffice.org/wiki/Dictionaries#English_.28AU.2CCA.2CGB.2CNZ.2CUS.2CZA.29

and when building the Ispell dictionary I got the following error

ERROR:  invalid byte sequence for encoding "UTF8": 0xe9640a
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".
CONTEXT:  line 220 of configuration file "C:/Program Files/PostgreSQL/8.3/share/tsearch_data/en_gb.dict"

CREATE TEXT SEARCH DICTIONARY english_ispell (
    TEMPLATE = ispell,
    DictFile = en_GB,
    AffFile = en_GB,
    StopWords = english
);