The only thing I can think of that has changed in my system is that I installed the K4 player and maybe added a couple of libraries to it. Is there some way that would corrupt the VEPRO relationship with K3.5?
Edit: A couple of restarts and a day later 5814 32-bit is loading k3.5 again, so maybe it was nothing. Getting a K4 Player upgrade now. Will see if it loads into 5814 64-bit shortly.