Yes indeed, chexmix, recommended change was made on all affected lines. Here's the revised test script:

use Spreadsheet::Read;
my $inbook = "Data_File.xlsx";
$book = ReadData ($inbook);
my @x = qw(F G H I J K);
for my $sheet_index (1 .. $sheet_count) {
    my $sheet = $book->[$sheet_index] or next;
    foreach (@x) {
       $name = $sheet{"${_}28"};
       $strain = $sheet{"${_}29"};
       $initdensity = $sheet{"${_}30"};
       $finaldensity = $sheet{"${_}31"};
       $avedensity = $sheet{"${_}32"};
       print "Found sheet with label: $sheet{label}\n";
       print "COL=$_ $name $strain $initdensity $finaldensity $avedens
+ity\n";
    }
}
[download]

Hopefully it helps you see my error. Regards, Hammer