The following is a paraphrase from the official docs, based on the "Less Easy Path."

HOW TO GET MT-BLACKLIST WORKING ON EMPLOYEES.ORG

MT-Blacklist is an anti-spam plugin for Movable Type blogs. It runs on MT v2.6 (http://www.movabletype.org) or later and can be found here:

http://www.jayallen.org/projects/mt-blacklist/

However, on employees.org, MT-Blacklist will not run in its simplest form. It requires the storable perl module: this is installed on the server, but writes in a native FreeBSD form rather than that required by MT-Blacklist. Consequently, users will need to set up YAML, as directed in the MT-Blacklist installation instructions and re-covered here.

1. To begin with, install the MT-Blacklist files from the zip as usual(remember that these should all be transferred to the server in ASCII mode, where MT_DIR is the location of your MT installation):

MT_DIR/mt-blacklist.cgi <--- Should be in the same directory as mt.cgi
MT_DIR/plugins/Blacklist.pl 
MT_DIR/extlib/jayallen/Blacklist.pm
MT_DIR/extlib/jayallen/MTBlPing.pm
MT_DIR/extlib/jayallen/MTBlPost.pm

1. Create a directory in MT_DIR/extlib/jayallen called Blacklist_Config. The new directory should be in the same directory as the Blacklist.pm file. Set the permissions on the new directory to 777 (-rwxrwxrwx):

MT_DIR/extlib/jayallen/Blacklist_Config/......

1. Open your Blacklist.pm file in a text editor (i.e. not Microsoft word. Notepad or Wordpad will do if you're not in love with Vi) and near the top of the file, you will see a block of text like this:

##################################################
#
# PATH TO FILESYSTEM-BASED BLACKLIST CONFIGURATION
#
# [ ..snip.. ]
#
# $blacklist_config_directory = '/path/to/extlib/jayallen/Blacklist_Config/';
#
##################################################

Replace the part in quotes - /path/to/extlib/jayallen/Blacklist_Config/ - with the real path to your Blacklist_Config directory and then remove the # sign in front of the line. Make sure that the path is enclosed in single quotes with no spaces at the ends, as it was originally. For example:

$blacklist_config_directory = '/users/username/WWW/mt-install/extlib/jayallen/Blacklist_Config/';

1. Re-upload this file, in ASCII mode, replacing the old one.
2. Next, download the YAML files from the jayallen page, here:

http://www.jayallen.org/projects/mt-blacklist/YAML_extlib.tar.gz

This is only a partial install of YAML, but includes everything needed.

1. Put the entire contents (the yaml.pm file and the YAML/ subdirectory) into your extlib directory:

MT_DIR/mt-blacklist.cgi      <--- Same place as mt.cgi, remember?
MT_DIR/plugins/Blacklist.pl 
MT_DIR/extlib/jayallen/Blacklist.pm
MT_DIR/extlib/jayallen/MTBlPing.pm
MT_DIR/extlib/jayallen/MTBlPost.pm
MT_DIR/extlib/jayallen/Blacklist_Config/
MT_DIR/extlib/Yaml.pm
MT_DIR/extlib/YAML/Error.pm
MT_DIR/extlib/YAML/Family.pm
MT_DIR/extlib/YAML/Node.pm
MT_DIR/extlib/YAML/Transfer.pm

1. Run up the MT Blacklist main page (MT_DIR/mt-blacklist.cgi) in your browser and it should all work! If not, check the troubleshooting pages:

http://www.jayallen.org/projects/mt-blacklist/latest/index#troubleshooting