RTModel: 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/RTModel - from package: topp

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

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