Turns out people still use NDE, but it doesn't install on Vista. I finally bit the bullet and put a installed a copy of Vista in VM Fusion on my MacBook, and confirmed that the installation was broken. Fearing I'd have to compile NDE for Vista (a challenge as it was built using the wonderful Borland 5.02 C++ compiler and IDE, now defunct). Turns out, it's the install package itself that's broken (built using Install Shield). The Inno Setup installer I use for TreeView X works fine, however.
The upshot is, if you use(d) NDE and have Vista, download a new copy of NDE from the web site, and it should work. Thanks to Mike Polcyn at the Southern Methodist University, Dallas, for the prompting that finally got this done.