You have two different sets of variables you're using. At the top-most scope of the file, you've declared the lexicals $givenname, $surname, and $middle_initial; these three are set by the first conditional (if ($adduserargs == 2 || $adduserargs == 3){ ... }</c), and are visible to the adduser() function.  Then you have three other lexicals with the same name that are declared and set in the second conditional (<c>elsif ($adduserargs == 0) { ... }). They are not visible to your adduser() function which ends up looking at variables with no values in them.