SPASS: 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/SPASS - from package: spass

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