ircd-ircu: 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/sbin/ircd-ircu - from package: ircd-ircu

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

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