rpmdep.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/rpmdep.pl - from package: rpmorphan

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

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