@cogreslab - do the midi rigs work? do the AU rigs works?
if the AU rigs work, and samplers/cello etc don't then i suspect you have not installed the resources correctly...
see here: http://www.eigenlabs.com/forum/threads/id/1418/
(some one else with a similar problem, its not the simplest part of the install, but you only have to do it once on the machine)
if the AU rigs don't work, have you checked the Audio settings in the menu - particularly if you have a soundcard installed.
(I'm of course assuming sound works from all other applications you have installed)
other than that I would suggest you create a new topic on here, and give a few more details about the machine, operating system (and version) etc ... what eigenharp (pico/tau/alpha)? and why you think its working/not working.
etc