mkjambase: 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:

/usr/bin/mkjambase - from package: jam

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

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