So this is what I believe you currently have , expressed as partitions (for ease of thinking/debugging/vocabulary)

#!/usr/bin/perl --
use strict; use warnings; use Data::Dump qw/ dd /;
my @want = (11, 9, 10);
#~ sum(0, 3, 8),
#~ 9,
#~ sum(5, 2, 0, 2, 1)
my @bad_ari = (0, 3, 8, 9, 5, 2, 0, 2, 1); 
my $min = 5; # minimal "goodness"

my @partition = [];
for my $val ( @bad_ari ){
    push @{ $partition[-1] }, $val;
    if( $val >= $min ){
        push @partition, [];
    }
}
dd( \@partition ); ## [[0, 3, 8], [9], [5], [2, 0, 2, 1]]
__END__
[download]

So compared to what you got that was wrong (11, 9, 5, 4) you can see that 2,0,2,1 doesn't add up to four it adds up to five, so you have off by one error in your c style for loop

Also, like Lennotoecom says , maybe what you want is wrong as well .... I wouldn't know :)