rootplot: 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/rootplot - from package: rootplot

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

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