xplot: 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 - from package: xplot

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

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