delete_spam: 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 Debian possible default full paths are:

/usr/bin/delete_spam - from package: trac-email2trac

You may install the required package with command apt-get install {package}

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