FWIW, I just finished fixing the same problem on a Win7 system. Rather than delete all of the files listed in post #111, all I had to do was rename the subdirectory C:\Users\myusername\AppData\Local\Sony Corporation\Reader\v
I renamed the directory "v" to "badv" and the reader software started right up. FWIW, it didn't even create a fresh "v" directory for itself. Evidently, something there was corrupt but apparently unnecessary.
Aargh. If you're reading this and this helps, I'm glad to have saved you the heartaches we've been through.