External Email - Use Caution

Mac OS comes with perl 5.18.. The module MNI/Startup.pm is not part of standard perl, and so it is provided in the freesurfer distribution. When you source either the FreeSurferEnv.csh or FreeSurferEnv.sh script the environment variable MNI_PERL5LIB should get set to $FREESURFER_HOME/mni/lib/../Library/Perl/Updates/5.12.3 You should be able to ls that path and see an MNI Perl module there, i.e., the file MNI.pm.

Subsrquently, the FreeSruferEnv scripts add MNI_PERL5LIB into the environment variable PERL5LIB. But if something in the cluster environment is unsetting/setting PERL5LIB after FreeSurferEnv runs, then freesurfer will not be able to find the module. You need to check the (final) values of MNI_PERL5LIB and PERL5LIB in the cluster environment.