I've replaced the original code by:

use CGI;
my ($q,$INPUT);
undef %$q;
$q = new CGI;
$INPUT = $q->Vars;
[download]

As far as Sifmole's statement that I have no understanding of what my previous code did: I fully understood it. I greatly appreciate everyone's help, but I learned CGI using that block of statements, not "use CGI"; consequently, it took more work than just adding "use CGI" in there. For example, I didn't know I'd have to create a new CGI scalar.

Everything works nicely now. Thanks to everyone for your help :)

-Adam