jfs_fsck: 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/jfs_fsck - from package: jfsutils

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

On Debian possible default full paths are:

/sbin/jfs_fsck - from package: jfsutils

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

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