flpsed: 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/flpsed - from package: flpsed

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

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