invalid byte sequence for encoding "UTF8":

All,

I have a new postgresql<8.3.4> build on linux<CentOS5> with PHP talking to
this database. If I try and update or insert on data that has special
characters I get this error:

ERROR: invalid byte sequence for encoding "UTF8": 0xa9
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".
STATEMENT: UPDATE preferences SET property = $1,preference_value =
$2,comment = $3,topic = $4 WHERE app_hash =
'50e2606ed950e8021d64349b49f4ee48'

I have read some articles about client_encoding but I do not know how to
get around this error.

Any help or support appreciated.
Thanks in advance,
Kulmacet