I too cannot launch 3.1 on my machine, but I believe that it is because I am running it on a virtual PC on my Mac. According to Sony, this won't work (that's a first... anything else has always worked on the virtual PC.)
However, there is apparently another way that 3.1 won't launch. Perhaps this might help some people:
http://www.kb.sony.com/selfservice/v...Id=1&mdl=null#