my @a=`awk '\$1 ~ /$_[0]/' useful_dat.tab |cut -f 2,3|sort|uniq`:

That's a compile error. I assume you meant (with a semicolon):

my @a=`awk '\$1 ~ /$_[0]/' useful_dat.tab |cut -f 2,3|sort|uniq`;
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my $object=test_element;

use strict and warnings. Should that be... ?

my $object = 'test_element';
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• Show the exact errors messages you get.
• Show us a few lines of useful_dat.tab