use strict;
use warnings;
local $/;
my $data = <DATA>;
$data =~  s/COMMENT:(?:(?!-----).)*-----//gs;        
print $data;

output:
-------
AUTHOR: bobMonk
TITLE: Monk Software Chart
STATUS: Publish
CATEGORY: Monks
DATE: 05/21/2006 11:36:16 AM
-----