vde_switch: 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

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/vde_switch - from package: vde2

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