pfstag: 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/pfstag - from package: pfstools

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