Mac OS X 10 and later versions are based on FreeBSD, which is a Unix flavor and comes with Perl (v5.6 on Jaquar and v5.8 on Panther) already installed. Just make sure you download the correct version of Vect built for your OS version. You may want to follow the same environment setups for Unix machines to run Vect generated Perl scripts from a command line.
Mac OS 9 or earlier was not supported by Vect, sorry, but the Perl programs Vect generates can still run on these OS. You need to go to MacPerl homepage to download MacPerl for older version of Mac OS and install it onto your machine.
See the detailed information Apple provided to configure and execute X11 applications on your Mac: