dispcalGUI-synthprofile: 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/dispcalGUI-synthprofile - from package: dispcalgui

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

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