foremost: 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/foremost - from package: foremost

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

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