syslog-summary: 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/syslog-summary - from package: syslog-summary

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

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