@Ruddel,
While many programs may continue to work on several OS versions after the one they are designed for, there are no guarantees. Using any software product long after it's discontinued carries what should be fairly obvious risks of incompatibilty.
Considering that Windows XP was the target OS at the time Homesite 5.5 was released, I'm not surprised that it won't run reliably on an OS that is three generations past that. While Homesite 5.5 was a fine tool for ColdFusion development, there are many good (and some free) alternatives available that will run on the latest OS. Time to move on and update your toolbox.
-Carl V.
