I've just noticed that the survey module, the db/*.sql files do a whole lot of inserts, including the ID field.
I don't know how mysql deals with this, but it breaks in postgres.
In postgres, when you create a table with SERIAL PRIMARY KEY, it will automatically create a sequence for you. Doing a whole lot of inserts with ID hard coded gets the sequence out of sequence.
Sometime today I will add in a reset for the sequence to the right number, someone with more mysql fu than me may want to change mysql.sql as well.
IMHO, We should also change the db/*.sql files to not put ID into the sql at all and let the database deal with it, but going forward we definitely need to reset the sequence.