UCPP_ROOT just points to the root of the version of UC++ to be used, e.g. for this version:
setenv UCPP_ROOT /cs/research/coside/fsfb/croissant/coside/uc++2.0.0a3
similarly PVM_ROOT, which might be set to
setenv PVM_ROOT /cs/research/coside/fsfb/croissant/coside/pvm3
finally PVM_ARCH gives the architecture name in the format used by PVM. This should be set in a .cshrc (or equivalent) as follows:
setenv PVM_ARCH `${PVM_ROOT}/lib/pvmgetarch`