I've tried V1 as well, with the same error.
It I create the "sequence" table and add the "bb_message_id_seq" as a column value there with a corresponding sequence value in the other column, this works fine. In other words, it works as if I had defined the generator strategy to be TABLE instead of SEQUENCE. I've read that a Toplink bug did this whenever the PK was not of type serial, but my primary key IS of type serial...
[Message sent by forum member 'mariusw' (mariusw)]
http://forums.java.net/jive/thread.jspa?messageID=220631