Brian,
Nvda braille works fine most of the time, but from time to time it stops working.
Jaws braille works, but I don't know how well or consistently; I don't use jaws normally.
Even narrator braille can work if I choose a different default driver.
The nvda log has error messages in it, but I don't know what to do with them.
Perhaps somebody who knows what they mean could prescribe a remedy.
http://nyx.net/~btew/briantew.nvdalog.txt