plotit: command not found

Have You tried accessing the binary with the full path?

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/plotit - from package: python-wxmpl

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