ldconfig.real: 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:

/sbin/ldconfig.real - from package: libc-bin

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

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