[Exim] error setting subject for autoreply with öäü

hello.

i've exim with mysql for user, aliases, autoresponder, forwarder and
lots more.

in different cases i get the error

    Expansion of ""
mysql_autoresponder_delivery transport contains non-printing character
252

after more research it seems that the subject i set for the
autoresponder do not allow äöüÖÄÜ...?

thanks for help.

regards Karl-Heinz