dspam_notify: 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/bin/dspam_notify - from package: dspam

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

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