dumptable: 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/dumptable - from package: cjdns-tools

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

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