sdpa: 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/bin/sdpa - from package: sdpa

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