Alan,
> The version of Windows Vista I am attempting to try rpVT on is Home
> Premium. The rpVT is the newest. With either /ZB1 or ZB command
/ZB1 no longer works with the "B" builds of rpVT such as B422.
> the application opens but control is not passes back to ZtreeWIN
> and rpVT does not stay in the foreground.
Works here with the only Vista (business) I have handy. I'll try it on a Home Premium, but that won't happen before the weekend.
In the meantime, just to eliminate the simple things... Doublecheck that you have the same switches as under XP, and the paths are correct. Also make sure that you run both ZTree and rpVT the same way - either normally, or elevated "as admin".
Cheers,
Liviu