mpqcval: 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/mpqcval - from package: mpqc-support

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

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