rtdCubeDisplay: 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

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/rtdCubeDisplay - from package: skycat

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