feedgnuplot: 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/feedgnuplot - from package: feedgnuplot

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