Mysql – Ubuntu / MySQL / Percona XtraBackup gives error “sh: 1: xtrabackup_55: not found”

Hello I installed Ubuntu 12.04.2 LTS on a fresh box.

This installed MySQL 5.5.29.

I installed percona-xtrabackup-2.0.6-521.tar.gz, and moved the executables to /usr/bin/

But innobackupex is giving an error: "sh: 1: xtrabackup_55: not found"

david@server1:/usr/bin$ sudo innobackupex --user=root --password=123 /home/david/dbb/
[sudo] password for david: 

InnoDB Backup Utility v1.5.1-xtrabackup; Copyright 2003, 2009 Innobase Oy
and Percona Ireland Ltd 2009-2012.  All Rights Reserved.

This software is published under
the GNU GENERAL PUBLIC LICENSE Version 2, June 1991.

130401 12:17:04  innobackupex: Starting mysql with options:  --password=xxxxxxxx --user='root' --unbuffered --
130401 12:17:04  innobackupex: Connected to database with mysql child process (pid=1488)
130401 12:17:10  innobackupex: Connection to database server closed
IMPORTANT: Please check that the backup run completes successfully.
           At the end of a successful backup run innobackupex
           prints "completed OK!".

innobackupex: Using mysql  Ver 14.14 Distrib 5.5.29, for debian-linux-gnu (x86_64) using readline 6.2
innobackupex: Using mysql server version Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.

sh: 1: xtrabackup_55: not found
innobackupex: fatal error: no 'mysqld' group in MySQL options

The files are present and executable:

david@server1:/usr/bin$ ls -l inno*
-rwxr-xr-x 1 root  root  108823 Mar 19 14:24 innobackupex
lrwxrwxrwx 1 david david     12 Mar 19 14:24 innobackupex-1.5.1 -> innobackupex
-rwxr-xr-x 1 root  root   10096 Jan 16 17:24 innochecksum
-rwxr-xr-x 1 root  root  400192 Jan 16 17:24 innotop
david@server1:/usr/bin$ 
david@server1:/usr/bin$ ls -l xtra*
-rwxr-xr-x 1 root root  9799993 Mar 19 14:21 xtrabackup
-rwxr-xr-x 1 root root  8361704 Mar 19 14:24 xtrabackup_51
-rwxr-xr-x 1 root root 12699861 Mar 19 14:15 xtrabackup_55
david@server1:/usr/bin$ 

Path is correct:

david@server1:/usr/bin$ echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

I get the same results if I run

innobackupex 
./innobackupex 
sudo innobackupex 
sudo ./innobackupex 

Any ideas?