Don't use Crypt::DES directly. Use it via Crypt::CBC instead. Crypt::CBC is designed to handle chaining issues (when the length of the plaintext is more than 8 bytes) and padding issues (when the length of the plaintext is not a multiple of 8 bytes).

use Crypt::CBC;

my $key = pack("H16", "0123456789ABCDEF");
my $plaintext = 'This data is hush hush';
print("$plaintext\n");

my $cipher = Crypt::CBC->new(
   -cipher => 'DES',
   -key    => $key,
);

my $ciphertext = $cipher->encrypt($plaintext);
print("$ciphertext\n");

my $recovered = $cipher->decrypt($ciphertext);
print("$recovered\n");
[download]

Untested.

Update: Added example.

Update: I forgot to mention the following:

By the way, I recommend against DES. It is outdated and easy to crack. By simply changing 'DES' to 'Blowfish', your encrypted data will be much more secure. You could also use 'Rijndael' (aka AES) if you supply a 32 byte key.