I'm running Vetbot5 on Vista.
Didn't need to do anything. One odd thing though is that the Verbot main folder is in the Windows vista 'user' area, not the 'Program Files' area.
Exact location of mine is:
This is a pretty strange place to install the main files, and I could see this being problematic for many. Especially those using heavy duty disk cleaners, or non-standard drive / partition settings.