vttest: 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 CentOS possible default full paths are:

/usr/bin/vttest - from package: vttest

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/vttest - from package: vttest

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

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