So here’s a quick tip. If you ever get your FreeNas install dorked up so bad that the Web-GUI stops working, grab your database file before you reinstall so you don’t have to re-configure.
The db file lives at:
/data/freenas-v1.db

You can then re-install a fresh FreeNas, drop this back in place via the webGUI and you should be up and running right where you were.

Not that I’d ever need to do something like that.

Edit:

So the really slick way to fix this is grab a FreeNas upgrade CD, slam it into the Nas box.  Boot from it.  Then let it “upgrade” your install and preserve your settings.