darkjobworker: 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/sbin/darkjobworker - from package: darkserver-importer

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

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