pspp: 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/pspp - from package: pspp

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