As I mentioned previously, the issue with with Vista - not with the MS Project version. It's one of Vista's many security "features" that doesn't allow Project Transit to run. This is something we are currently investigating, but we don't have a specific target release identified at this time.
I'm not sure why it says all of our utilities are Vista compatible on the download page - I just saw that myself. I'll bring that to the attention of the appropriate people here. The Project Transit help file only notes support for Windows versions up to XP.