vss2xhtml: 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/vss2xhtml - from package: libvisio-tools

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

Error in other languages:
vss2xhtml: bevel nie gevind nie
vss2xhtml: comandă negăsită
vss2xhtml: comando não encontrado
vss2xhtml: commande introuvable
vss2xhtml: command not found
vss2xhtml: käsku ei ole
vss2xhtml: không tìm thấy lệnh
vss2xhtml: komanda nerasta
vss2xhtml: Kommando nicht gefunden.
vss2xhtml: kommandot finns inte
vss2xhtml: komut yok
vss2xhtml: nie znaleziono polecenia
vss2xhtml: níor aimsíodh an t-ordú
vss2xhtml: no se encontró la orden
vss2xhtml: no s'ha trobat l'ordre
vss2xhtml: opdracht niet gevonden
vss2xhtml: parancs nem található
vss2xhtml: perintah tidak ditemukan
vss2xhtml: príkaz nenájdený
vss2xhtml: příkaz nenalezen
vss2xhtml: команда не найдена
vss2xhtml: командата не е открита
vss2xhtml: 命令找不到
vss2xhtml: コマンドが見つかりません