I'm not particularly familiar with California taxes, but a "business" tax of $800 sounds like California's annual $800 tax on LLCs. Your wife's business is a sole proprietorship and is presumably not an LLC, so I don't see where there would be any extra $800 California tax on her self-employment income. It seems unlikely that this has anything to do with your individual income tax return; the $800 annual LLC tax is paid separately. It might make sense to ask the FTB if the $800 tax is the annual tax on LLCs and ask why they think that you or your wife have an LLC.
[Edit: I see that TomD8 beat me to it by a few minutes.]
