mip6d: 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 CentOS possible default full paths are:

/usr/sbin/mip6d - from package: mipv6-daemon

You may install the required package with command yum install {package}
Error in other languages:
mip6d: bevel nie gevind nie
mip6d: comandă negăsită
mip6d: comando não encontrado
mip6d: commande introuvable
mip6d: command not found
mip6d: käsku ei ole
mip6d: không tìm thấy lệnh
mip6d: komanda nerasta
mip6d: Kommando nicht gefunden.
mip6d: kommandot finns inte
mip6d: komut yok
mip6d: nie znaleziono polecenia
mip6d: níor aimsíodh an t-ordú
mip6d: no se encontró la orden
mip6d: no s'ha trobat l'ordre
mip6d: opdracht niet gevonden
mip6d: parancs nem található
mip6d: perintah tidak ditemukan
mip6d: príkaz nenájdený
mip6d: příkaz nenalezen
mip6d: команда не найдена
mip6d: командата не е открита
mip6d: 命令找不到
mip6d: コマンドが見つかりません