rgb2pat: 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/rgb2pat - from package: xautomation

You may install the required package with command apt-get install {package}
Error in other languages:
rgb2pat: bevel nie gevind nie
rgb2pat: comandă negăsită
rgb2pat: comando não encontrado
rgb2pat: commande introuvable
rgb2pat: command not found
rgb2pat: käsku ei ole
rgb2pat: không tìm thấy lệnh
rgb2pat: komanda nerasta
rgb2pat: Kommando nicht gefunden.
rgb2pat: kommandot finns inte
rgb2pat: komut yok
rgb2pat: nie znaleziono polecenia
rgb2pat: níor aimsíodh an t-ordú
rgb2pat: no se encontró la orden
rgb2pat: no s'ha trobat l'ordre
rgb2pat: opdracht niet gevonden
rgb2pat: parancs nem található
rgb2pat: perintah tidak ditemukan
rgb2pat: príkaz nenájdený
rgb2pat: příkaz nenalezen
rgb2pat: команда не найдена
rgb2pat: командата не е открита
rgb2pat: 命令找不到
rgb2pat: コマンドが見つかりません