fsarchiver: 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/sbin/fsarchiver - from package: fsarchiver

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

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