As perlmonkey has noted this problem is due to $VAR1 being undeclared. A remedy to this is to turn on $Data::Dumper::Terse which will do away with the $VAR1 e.g

use Data::Dumper;

local $Data::Dumper::Terse = 1;

my $hashref = {
  aaa =>  1,
  bbb =>  2,
  ccc =>  3,
};

print "hashref : " . Dumper($hashref);

my $evalled = eval(Dumper($hashref));
print "evalled : " . Dumper($evalled);


__output__

hashref : {
          'ccc' => 3,
          'bbb' => 2,
          'aaa' => 1
        }
evalled : {
          'ccc' => 3,
          'bbb' => 2,
          'aaa' => 1
        }
[download]

Although you'll want to be careful you're not dumping a self-referential data structure

use Data::Dumper;

local $Data::Dumper::Terse = 1;

my $x;
$x = \$x;

__output__

\$VAR1
[download]

See. the Data::Dumper docs for more info.
HTH

_________
broquaint