ldaprenameuser: 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 Debian possible default full paths are:

/usr/sbin/ldaprenameuser - from package: ldapscripts

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

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