Unfortunately there's no single answer to this - it all depends on the setup of your server. If you have telnet access to your server, you can find out by typing 'pwd' from the directory where your .html files reside, but if not your hosting company should be able to tell you.
Unfortunately, the company that is hosting my site told me I do not have telnet access because I share the server with too many people and they have security issues if I have telnet access. I asked them to give me the Unix directory, (and told them where the file currently resides, but have not heard back).
Are there standard ways that severs are setup that I could find out through trial and error?
I am getting a: No such file or directory error message. I know the file is on the server, but guess I have the Unix directory wrong.
It may be a case of miscommunication with your host... ask them specifically what the "file path" is to your html directory.
On one of my accounts the path to my cgi-bin is /home/username/virtual/cgi-bin, on another account it's /home/username/public_html/cgi-bin... and I've seen others that were much longer and more convoluted.
The first line of a perl script is generally something along the lines of: #!/usr/bin/perl
This tells the script where to find the perl interpreter. If this line does not match the actual location Perl on the system you are using it will generate a File Not Found error ("No such file or directory") On an old FreeBSD system I have an account on, for example, the admin installed it to /usr/local/bin/perl. You might wanna check the location.