EXS 24 Logic Sampler Users Group

I recently installed both TBO and the White Grand
pianos from SampleTekk and they play beautifully.
However, I also installed the White Sister, using the
same procedure, and although the raw samples sound
fine, when I call up the piano in exs all I hear is
white noise on every note. In desparation I've tried
several different file structures for the instrument
file but always get the same result. 
Any suggestions?
Thanks, JP