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

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

On Debian possible default full paths are:

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

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

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