zvbi-chains: 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/zvbi-chains - from package: zvbi

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

On Debian possible default full paths are:

/usr/bin/zvbi-chains - from package: zvbi

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

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