mkfs.jfs: 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 CentOS possible default full paths are:

/sbin/mkfs.jfs - from package: jfsutils

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/sbin/mkfs.jfs - from package: jfsutils

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

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