validlocale: command not found

Have You tried accessing the binary with the full path?

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/validlocale - from package: locales

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