EXS 24 Logic Sampler Users Group

i just upgraded to v.6.0 and can't get any of my VST-instruments to work
(EXS, es1, etc...)  i'm using a M i/o 2882+dsp (which is recognized from my
firewire port) and MIDI is working fine.  i just can't get anything to play
from the comp (meaning, vst-instruments-- not audio).  i've replaces ASIO
drivers in the logic folder, rebuilt the desktop, toggled the sampling rate
and nothing seems to be working... i did have it working once, but can't
seem to get it working again... any suggestions? (please help!!)

always,
tv