loggen: 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/loggen - from package: syslog-ng

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

On Debian possible default full paths are:

/usr/bin/loggen - from package: syslog-ng-core

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

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