"user_preferences" not existing sounds like either a data-model loading error, or that your sources aren't properly synched.
The additional insert/duplicate key errors makes me think this problem of triggers and scripts both trying to insert default values may be happening on tables other than user_preferences...
Did you update to Beta3? Try a virgin installation, if you can. I just did so with the latest CVS tree (Beta3 with a small number of bug fixes) about 36 hours ago, and had no problem installing.
