aoss: 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/aoss - from package: alsa-oss

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

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