nsdb-delete-fsl: 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/nsdb-delete-fsl - from package: fedfs-utils-admin

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