wd_keepalive: 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/sbin/wd_keepalive - from package: watchdog

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

On Debian possible default full paths are:

/usr/sbin/wd_keepalive - from package: watchdog

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

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