While installing Team Foundation Server 2010 beta 2 in my current project I encountered the following error while running the Team Foundation Build Configuration Wizard: 

Cannot start service TFSBuildServiceHost on computer 'SERVERNAME'

After checking the Event Log, I saw the following error:

The Visual Studio Team Foundation Build Service Host service depends on the Remote Access Connection Manager service which failed to start because of the following error: 

The service cannot be started, either because it is disabled or because it has no enabled devices associated with it.

That service was disabled on the server and after setting it to manual or automatic, the configuration wizard was able to successfully start the TFSBuildServiceHost service.

Please note that the Remote Access Connection Manager in turn is dependent on the Telephony Service, so if it's Disabled as well you need to change the settings for that service too.

Happy configuring!