flowgrindd: 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/lib/debug/usr/sbin/flowgrindd - from package: flowgrind-dbg
/usr/sbin/flowgrindd - from package: flowgrind

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