I get the active sense that I'm not making myself clear. Here is my situation. I was able to get both Sonar and Sibelius to communicate with Vienna Ensemble version 2.x. I did this by rolling back my computer to a restore point which I created before installing Vienna Ensemble version 4.x. When I installed version 4.x on top of version 2 without having first uninstalled version 2, I was eventually able to get Sonar to communicate with Vienna Ensemble. But I was never able to get Sibelius 5 or 6 to communicate with Vienna Ensemble 4.x. I'm running Windows XP Home on this machine. I know that my directory entries are correct.
Today, I undid the roll back I had done that brought my computer back to Vienna Ensemble version 2.x and, with version 4.x the current version, I completely uninstalled and reinstalled version 4.x. Still, I couldn't get Sibelius to communicate with it. My communication test involved bringing up a string quartet in Sibelius which used a Sibelius Vienna Solo Strings sound set I got from your website, and which was propperly installed and works under Vienna Ensemble 2.x. When i opened Sibelius 5 with version 4.x, Vienna Ensemble would not open and the requisite Vienna Instruments and matrix files would not load.
Since everything seems to work under version 2.x, I've decided to return my system to the old restore point with Vienna Ensemble 2.x and leave things the way they are. Both Sonar 8.5 Producer and Sibelius versions 5 and 6 seem to be working agreeably at this time and unless there's some compelling reason to continue trying to figure out why it won't work, I'm going to simply leave things as they are until I buy a new computer, probably a Mac Pro, and reinstall everything under Logic, perhaps.
One final thought. All the installation of instruments in Vienna Ensemble and channel assignment is really no fun if your vision is poor. Not only that, your directory manager doesn't even respond to screen readers. The directory manager should, because it's a basic file folder structure that looks just like Windows Explorer which does respond to screen readers.
Best,
Kevin