msgchk: 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/mh/msgchk - from package: nmh

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

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