There are three main internal distributions of FreeSurfer available at the NMR Center. To use a distribution, set your FREESURFER_HOME environment variable to the directory of the distribution and then source the FreeSurferEnv.csh file in that distribution. For example:
setenv FREESURFRER_HOME ~inverse/freesurfer_alpha source $FREESURFER_HOME/FreeSurferEnv.csh
Note that you may still have to set up your path. Be sure you are using the right binaries with the which command.
See