mpqc: 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/mpqc - from package: mpqc

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

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