_carettah_main_: 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
/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/_carettah_main_ - from package: carettah

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