spfqueue: 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/lib/debug/usr/sbin/spfqueue - from package: pfqueue-dbg
/usr/sbin/spfqueue - from package: pfqueue

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

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