doschk: 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/bin/doschk - from package: doschk

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

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