lstopo: 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/lstopo - from package: hwloc

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

On Debian possible default full paths are:

/usr/bin/lstopo - from package: hwloc-nox
/usr/bin/lstopo - from package: hwloc

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

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