hpitree: 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/hpitree - from package: openhpi32
/usr/bin/hpitree - from package: openhpi

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

On Debian possible default full paths are:

/usr/bin/hpitree - from package: openhpi-clients

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

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