ldbrename: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/ldbrename - from package: ldb-tools

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/ldbrename - from package: ldb-tools

You may install the required package with command apt-get install {package}

Error in other languages:
ldbrename: bevel nie gevind nie
ldbrename: comandă negăsită
ldbrename: comando não encontrado
ldbrename: commande introuvable
ldbrename: command not found
ldbrename: käsku ei ole
ldbrename: không tìm thấy lệnh
ldbrename: komanda nerasta
ldbrename: Kommando nicht gefunden.
ldbrename: kommandot finns inte
ldbrename: komut yok
ldbrename: nie znaleziono polecenia
ldbrename: níor aimsíodh an t-ordú
ldbrename: no se encontró la orden
ldbrename: no s'ha trobat l'ordre
ldbrename: opdracht niet gevonden
ldbrename: parancs nem található
ldbrename: perintah tidak ditemukan
ldbrename: príkaz nenájdený
ldbrename: příkaz nenalezen
ldbrename: команда не найдена
ldbrename: командата не е открита
ldbrename: 命令找不到
ldbrename: コマンドが見つかりません