You are referencing the "xls" file which is still binary. Change your filename to "spreadsheet.xml" and save the file as xml.

Using your first script with an "xls" file causes the error you see, however when I use it on the same file saved as "xml" it does not report an error.

Update

Here is some code to dump the xml file.

use strict;
use warnings;
use XML::Simple qw(:strict);
use Data::Dumper;  

my $config = XMLin('./Book1.xml',forcearray => 1,keyattr => ['']);
print Dumper($config);
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