fdp: 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/fdp - from package: graphviz

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

On Debian possible default full paths are:

/usr/bin/fdp - from package: graphviz

You may install the required package with command apt-get install {package}

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