I have to remove the prefs file as well? No one has ever told me that part before. Why would your software engineers develop their installers in such a customer-unfriendly way? (no, I don't actually expect an answer for that question)
I wish I had more time to beta-test your overly-complex installer processes, but I don't. So until I receive the thrice-requested 9.5 install CD, I have much better things on which to spend my time.