perdition.pop3: 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 Debian possible default full paths are:

/usr/sbin/perdition.pop3 - from package: perdition

You may install the required package with command apt-get install {package}
Error in other languages:
perdition.pop3: bevel nie gevind nie
perdition.pop3: comandă negăsită
perdition.pop3: comando não encontrado
perdition.pop3: commande introuvable
perdition.pop3: command not found
perdition.pop3: käsku ei ole
perdition.pop3: không tìm thấy lệnh
perdition.pop3: komanda nerasta
perdition.pop3: Kommando nicht gefunden.
perdition.pop3: kommandot finns inte
perdition.pop3: komut yok
perdition.pop3: nie znaleziono polecenia
perdition.pop3: níor aimsíodh an t-ordú
perdition.pop3: no se encontró la orden
perdition.pop3: no s'ha trobat l'ordre
perdition.pop3: opdracht niet gevonden
perdition.pop3: parancs nem található
perdition.pop3: perintah tidak ditemukan
perdition.pop3: príkaz nenájdený
perdition.pop3: příkaz nenalezen
perdition.pop3: команда не найдена
perdition.pop3: командата не е открита
perdition.pop3: 命令找不到
perdition.pop3: コマンドが見つかりません