dspamc: 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/dspamc - from package: dspam-client

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

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