vps: 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/sbin/vps - from package: util-vserver

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

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