The log file says:
unable to bind any inbound sockets on port 873
The service appears to start and in about five seconds it stops. Any clues? netstat reveals nothing on port 873. I tried port 8730 in case it just did not like a privileged port.
It seems definitely that port 873 is busy somehow. I assume that you have administrator privileges on the machine. Is it a SP2+ machine ? Built-in firewall may block port 873.