rpmusage.pl: 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/rpmusage.pl - from package: rpmorphan

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

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