hp_hpxtest: 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/hp_hpxtest - from package: healpix-c++

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

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