xplot.org: 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/xplot.org - from package: xplot-xplot.org

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

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