ntsysv: 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/ntsysv - from package: ntsysv

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

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