Hi,
Can you post your config under "system syslog"
"show configuration system syslog"
If your router has to send syslog messages to an outside syslog server you can trace the messages sent with this command:
"monitor traffic interface <int>"
you can also see if the local login works
By default you have a message file that is "loaded" with some informations
type
"show log messages" to see if something goes in it
or just use "monitor start message" to see if messages are going into it.
Hope This will Help You