Function sequence error on delete or update

Hello,

Environment:
    Server: Red Hat 9.
    DataBase: PostgreSQL 7.3
    Client: Win98/XP
    Driver:
ODBC Driver 7.3.2 for
Windows.
Problem:
    I always get the message "Function sequence
error" when I try to execute a delete and there are no rows selected
for deletion.
    The same problem occurs with the UPDATE.

Do you know how to fix the problem or any workaround?

Thanks,

Jefferson Medeiros