vss2text: 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/vss2text - from package: libvisio-tools

You may install the required package with command apt-get install {package}
Error in other languages:
vss2text: bevel nie gevind nie
vss2text: comandă negăsită
vss2text: comando não encontrado
vss2text: commande introuvable
vss2text: command not found
vss2text: käsku ei ole
vss2text: không tìm thấy lệnh
vss2text: komanda nerasta
vss2text: Kommando nicht gefunden.
vss2text: kommandot finns inte
vss2text: komut yok
vss2text: nie znaleziono polecenia
vss2text: níor aimsíodh an t-ordú
vss2text: no se encontró la orden
vss2text: no s'ha trobat l'ordre
vss2text: opdracht niet gevonden
vss2text: parancs nem található
vss2text: perintah tidak ditemukan
vss2text: príkaz nenájdený
vss2text: příkaz nenalezen
vss2text: команда не найдена
vss2text: командата не е открита
vss2text: 命令找不到
vss2text: コマンドが見つかりません