gnobots2: 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/gnobots2 - from package: gnome-games-extra

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

Error in other languages:
gnobots2: bevel nie gevind nie
gnobots2: comandă negăsită
gnobots2: comando não encontrado
gnobots2: commande introuvable
gnobots2: command not found
gnobots2: käsku ei ole
gnobots2: không tìm thấy lệnh
gnobots2: komanda nerasta
gnobots2: Kommando nicht gefunden.
gnobots2: kommandot finns inte
gnobots2: komut yok
gnobots2: nie znaleziono polecenia
gnobots2: níor aimsíodh an t-ordú
gnobots2: no se encontró la orden
gnobots2: no s'ha trobat l'ordre
gnobots2: opdracht niet gevonden
gnobots2: parancs nem található
gnobots2: perintah tidak ditemukan
gnobots2: príkaz nenájdený
gnobots2: příkaz nenalezen
gnobots2: команда не найдена
gnobots2: командата не е открита
gnobots2: 命令找不到
gnobots2: コマンドが見つかりません