hpmount: 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 Debian possible default full paths are:

/usr/bin/hpmount - from package: hfsplus

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

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