jmcore: 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/jmcore - from package: ladish

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

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