Well.... Ai9 is a ~1999 app. Vista is a 2008 OS.
There are many applications made in the 90s that don't run on modern operating systems.
I would say it's a "problem" specifically. Basically you're trying to run ancient stuff on modern architecture. Time to upgrade Illustrator.
I think there's a compatibility mode issue... try right clicking on the exe file and in properties opt for the "run in 32bit compatibility mode" or some such... i don't have Vista so i can't be more specific.
Hope it points you in the rght direction at least...