kturtle: 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/kturtle - from package: kturtle

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

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