This section explain how to deal with error generated while downloading and installing add-on modules.

ERROR: Undefined subroutine &main::Get_module_list called at /home/www/html/cgi-bin//PlexumLib/sess.lib line xxx.

Solution:

Log-on to your server via FTP and navigate to the cgi-bin directory where PLEXUM PlexumLib directory is located, open the directory and set permissions to 666 or 644 on all .lib files, if that didn't work, try setting permissions on your cgi-bin and PlexumLib folder to 777 or 755.