d-rats: 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/d-rats - from package: d-rats

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