ka-forwarder: 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/sbin/ka-forwarder - from package: openafs-krb5

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

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