Problem with invalid byte sequence and log_min_error_statement

Hi,

i run the greatest database ever, postgresql-8.3, on debian etch

I am investigating some error messages in my log file:

Apr 15 08:04:34 postgres[20686]: [4-1] 2009-04-15 08:04:34 CEST ERROR:
invalid byte sequence for encoding "UTF8": 0x81
Apr 15 08:04:34 postgres[20686]: [4-2] 2009-04-15 08:04:34 CEST HINT:  This
error can also happen if the byte sequence does not match the encoding
expected by the
Apr 15 08:04:34 postgres[20686]: [4-3]  server, which is controlled by
"client_encoding".

I want to know which statement produces this error. I have

show log_min_error_statement ;
 error

show log_error_verbosity;
 default

so i think the error statement should be logged. Why is the error statement
not logged? Or do i need to set  log_error_verbosity to verbose to see the
statement producing the error?

I always see 0x81 and 0xe46973 as invalid byte sequence. Can someone give me a
hint what characters in which encoding those bytes might be?

kind regards
Janning