This is a simple problem. Just read the message body once, before your loop. Save it into a scalar, like so:

open MSGBODY, "$file"
    or die "Couldn't open $file: $!";
$message = join('', <MSGBODY>);

for $member (keys %CONTACT) {
    ...
    $fh = $msg->open;
    print $fh $message;
[download]

If you have to do some per-user processing of the message, then look into some of the text templating systems. (I personally recommend Template::Toolkit.)

--rjray