ovs-dpctl-top: 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
/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-dpctl-top - from package: openvswitch-switch

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