mhstore: 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/bin/mh/mhstore - from package: nmh

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