How about changing

## ensure some arguments are given
if ($#ARGV < 0) {
  print "\nPancho requires some flags to be specified.\nPlease try run
+ning ./pan
cho --help\n\n";
  exit(1);
}
[download]

To:

die "Pancho requires some flags to be specified. Please try running $0
+ --help"
   unless (@ARGV);
[download]