neato: 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/neato - from package: graphviz

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

On Debian possible default full paths are:

/usr/bin/neato - from package: graphviz

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

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