We have always untarred up to 7.1.0 and used it successfully. This was the good thing about FreeSurfer that did not require a client side installation. I am the administrator and I can tell you that installation of this software via root is infeasible for 100 computers.

Given your comment about 7.4.1 tarball being not installer, we want to know--has the installation mechanism changed since 7.4.1?