vss2raw: 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/vss2raw - from package: libvisio-tools

You may install the required package with command apt-get install {package}
Error in other languages:
vss2raw: bevel nie gevind nie
vss2raw: comandă negăsită
vss2raw: comando não encontrado
vss2raw: commande introuvable
vss2raw: command not found
vss2raw: käsku ei ole
vss2raw: không tìm thấy lệnh
vss2raw: komanda nerasta
vss2raw: Kommando nicht gefunden.
vss2raw: kommandot finns inte
vss2raw: komut yok
vss2raw: nie znaleziono polecenia
vss2raw: níor aimsíodh an t-ordú
vss2raw: no se encontró la orden
vss2raw: no s'ha trobat l'ordre
vss2raw: opdracht niet gevonden
vss2raw: parancs nem található
vss2raw: perintah tidak ditemukan
vss2raw: príkaz nenájdený
vss2raw: příkaz nenalezen
vss2raw: команда не найдена
vss2raw: командата не е открита
vss2raw: 命令找不到
vss2raw: コマンドが見つかりません