Guy:
Were you able to get Logic to open without it attempting to validate VI? If not, double-click the Logic Pro application icon, then hold down the Shift and Control keys until a dialog pops up or Logic is fully loaded. This known as AU Safe Mode. This will load only those Audio Units that have already passed the Audio Units Validation Tool. Once you've got Logic to open in this fashion, then go to the AU Manager which you can access as follows: Logic Pro Menu/Preferences/ Start AU Manager. Starting the AU Manager causes Logic itself to quit. Then find the Vienna Instruments on the list of Audio Units, check it and tell THE AU Manager to recheck it. At this point I would recommend a long walk around the block, a sip of good single malt or some other similarly diverting or anesthetizing activity - - since this going to take a while and will look like it has crashed once you see the spinning ball after the the progress bar as been going for a while. Do not panic, just keep diverting yourself. When you comeback, the AU Manager will, most likely announced that VI has passed validation.