hdapsd: command not found

Have You tried accessing the binary with the full path?

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/sbin/hdapsd - from package: hdapsd

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