ovs-tcpundump: 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/ovs-tcpundump - from package: openvswitch-switch

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

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