isnsd: 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/isnsd - from package: isns-utils

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

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