cdv: 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/lib64/erlang/lib/observer-0.9.10/priv/bin/cdv - from package: erlang-observer

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

On Debian possible default full paths are:

/usr/bin/cdv - from package: codeville
/usr/lib/erlang/lib/observer-2.0.2/priv/bin/cdv - from package: erlang-observer

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

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