dumpseg: 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/dumpseg - from package: nilfs-tools

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

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