I don't think you need the hypen. Just "log=log.txt". It will be found in UDKGame\Logs.
That said, nothing seems to happen for me. I get this:
Connected to database successfully!
Loaded 0 into cached player list!
Attempting to connect to RCON for announcements.
Server is running a newer protocol (v002).
You need to download a new version of RxCommand.
Cleared the cached players, they are assumed offline!
Nothing after that. No changes to my DB, etc.