I am not certain this pertains to Win 2008 (it very well may not) - however FWIW here are notes I made a year or two back when I was trying to get this to run as a service.
http://www.s-consult.com/2009/05/20/how-to-setup-hightowers-timekeeper-using-providex-web-server-to-run-as-a-service/