OK, I've gotten this sorted now.
Previous to this, when I reinstalled BeerSmith, it never walked me through any of that setup stuff. This, despite the fact that I uninstalled if from the control panel, removed the folder from "C:\Program Files\BeerSmith" and even edited my registry to remove all mentions of BeerSmith. Additionally I ran Vista's disk cleanup everytime I uninstalled and reinstalled.
I went through this routine 4 times. Each time the problem remained.
Then I ran an advanced search in Vista on the string 'beersmith'.
What I found was a directory within "C:\Users\username\AppData\Local\VirtualStore" which had backups of all of the contents of "C:\Program Files\BeerSmith"
To be extra anal, I deleted every single reference to BeerSmith that my advanced search found (which included my recipes which I backed up elsewhere. (Though I'm 99% sure all I needed to eliminate was the content of the VirtualStore
I removed this, turned the computer off all the way, re-downloaded BeerSmith and reinstalled it. Everything looks OK so far.