When configuring rsyslog on Solaris, you might not be able to use imuxsock. When starting rsyslog, the following message will appear if imuxsock is configured:
rsyslogd: imuxsock does not run because we could not aquire any socket
The reason is, that imuxsock can be used to monitor unix sockers, but it does not monitor the system log "socket" from Solaris, because it works in a different way. Instead of loading the imuxsock module in your rsyslog.conf you must use imsolaris. You only need to load imuxsock if you want to monitor other unix sockets.