pmidi: 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/pmidi - from package: pmidi

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

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