mksh-static: 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:

/bin/mksh-static - from package: mksh

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

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