If you have the Rasmol source I'd suggest to edit the
# DEPTHDEF = -DTHIRTYTWOBIT
# DEPTHDEF = -DEIGHTBIT
DEPTHDEF = -DSIXTEENBIT
Or to avoid another run of imake do the change directly
in the Makefile. I can supply you with the 16bit version
if you have any problems.
Steffen Moeller <moeller at ebi.ac.uk>