I overlooked that this was about conditionally loading the module somewhere between the OP and the post about HTTP::Status.

#! perl -slw

# This would normally be updated based on some condition in the code.
my $condition = 0;

# possibly very many lines of code go here

# Faking a condition in the code...
$condition ||= shift @ARGV;

if ($condition) {
  require HTTP::Status;
  import HTTP::Status;
  print RC_FORBIDDEN();  # as merlyn pointed out, we need to give the 
+parser a clue
}

__END__
P:\test>test4 0

P:\test>test4 1
403
[download]

This was really for my benefit and no one elses.