I am going to say some things that you will not like. I am sorry.
I must question your contention that you are a very good sys admin. First you seem to have little grasp on how a computer works. You downloaded some code and expected it to work. This is ridiculous. My guess is you are in charge of some computers possibly a server. You are probably better than most where you work and some may call you a Sys Admin. None of this makes you stupid, or a bad person.
Now you endevor to learn Perl but have already decided that Sys Admins and "coders" can not be the same person. This is untrue, silly and the people reinforcing this notion around you are sorely mistaken. They are neither stupid, nor bad people.
OK, now about where to Learn Perl.
Download Perl from ActiveState
Here at Perl Monks
Learning Perl on Win32 Systems
WIN32 Perl Scripting for Systems Administrators
Now that should take a lot longer than 21 days but you will become a great Sys Admin and proabably a damn fine coder.
As you learn to code you will come to respect knowledge and hopefully you will not download books! (If I misread your post I apologize but it reads as if you've found a scanned version of the book somewhere.)
No off with you! Learn.
There's more than one way to do it, but only some of them actually work.