rootinfo: 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/rootinfo - from package: rootplot

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

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