foo2slx: 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/foo2slx - from package: printer-driver-foo2zjs

You may install the required package with command apt-get install {package}
Error in other languages:
foo2slx: bevel nie gevind nie
foo2slx: comandă negăsită
foo2slx: comando não encontrado
foo2slx: commande introuvable
foo2slx: command not found
foo2slx: käsku ei ole
foo2slx: không tìm thấy lệnh
foo2slx: komanda nerasta
foo2slx: Kommando nicht gefunden.
foo2slx: kommandot finns inte
foo2slx: komut yok
foo2slx: nie znaleziono polecenia
foo2slx: níor aimsíodh an t-ordú
foo2slx: no se encontró la orden
foo2slx: no s'ha trobat l'ordre
foo2slx: opdracht niet gevonden
foo2slx: parancs nem található
foo2slx: perintah tidak ditemukan
foo2slx: príkaz nenájdený
foo2slx: příkaz nenalezen
foo2slx: команда не найдена
foo2slx: командата не е открита
foo2slx: 命令找不到
foo2slx: コマンドが見つかりません