In add.pl, trying including the full path (from your root directory) to the links.cfg file in the links.cfg require line at the top of the script. Sometimes that is all it takes.
If you have telnet access, log in and try to run the script from the shell prompt to see if it gives you any other errors. You may need to run it using the command, "perl add.pl".
If you have telnet access, log in and try to run the script from the shell prompt to see if it gives you any other errors. You may need to run it using the command, "perl add.pl".