JFractionLab: 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/JFractionLab - from package: jfractionlab

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

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