This a quick implementation of the algorithm description I gave before:

#!/usr/bin/env perl

use strict;
use warnings;

my %user_weight = (DREW => .5, TIM => 2,);
my ($tot_users, $tot_non_weighted, $tot_events);

while (<DATA>) {
        # Stuff data into Hash and get count of total events and users
        my ($user, $val) = split;
        $tot_events += $val;
        $tot_users++;
        $tot_non_weighted ++ unless exists $user_weight{$user};
}
my $number_of_weighed_parts;
$number_of_weighed_parts += $_ for values %user_weight;
my $indiv_part = $tot_events / ($tot_non_weighted + $number_of_weighed
+_parts);
print "The $tot_non_weighted non_weighted workers get each $indiv_part
+\n";
for my $weighted_user (keys  %user_weight) {
    print "$weighted_user gets ", $indiv_part * $user_weight{$weighted
+_user}, "\n";
}


__DATA__
TIM 150
JOE 124
JACK 111
KATE 145
DREW 177
[download]

And this prints the following output:

$ perl weight.pl
The 3 non_weighted workers get each 128.545454545455
DREW gets 64.2727272727273
TIM gets 257.090909090909
[download]

which seems correct (at least if I understood correctly what you are trying to do). You would probably want to add some rounding, but I leaves that to you.

Edit 15:41 UTC: corrected a bug in the above code and the output.

Edit2 16:40 UTC: I had not seen moritz's solution when I posted my messages above. My proposed solution (be it in English or in Perl code) is to a large extent equivalent, sorry for posting almost the same thing.