ctsim: 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/ctsim - from package: ctsim

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

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