numinterval: 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/numinterval - from package: num-utils

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

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