dumpRumorMill: 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/dumpRumorMill - from package: cjdns-tools

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

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