dumpgraph: 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/dumpgraph - from package: cjdns-graph

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

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