The examples you posted won't work, each lacks a string terminator (no closing "). The crude example below works for me where there is a space in the key name.

#!/usr/bin/perl

use strict;
use warnings; 
use Data::Dumper;
use Win32::TieRegistry( Delimiter => '/' );

my $value = $Registry->{ "HKEY_CURRENT_USER/Software/Microsoft/Windows
+/CurrentVersion/Group Policy" } ;
print Dumper $value;
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