ntfsmount: 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:

/bin/ntfsmount - from package: ntfs-3g
/usr/bin/ntfsmount - from package: ntfs-3g

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

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