rgbmap: 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/rgbmap - from package: liballegro4-dev

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

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