"Then before biting off the challenge of re-writing our build scripts in Team Build, we used the CruiseControl plug-in for TFS and adjusted the NAnt scripts to get code with the TF command.  The trick is to manually login with the account running the CruiseControl service and setup a TFS Workspace with the right directory mappings.  Then give CruiseControl's config file the full path to the solution it should watch.  It worked quite nicely.  If you stop the CruiseControl Windows service, you can run it from a command line and see all the console output for testing and debugging the build.  That should give you insight into all the reasons that a build fails.  Finally, we rewrote our build scripts in Team build using NUnit (instead of converting hundreds of tests to MS Test).  We used the MSBuild Community Tasks Project on Tigris.org to execute the NUnit tests.  The examples don't show it and the syntax isn't obvious, but you can use the build task syntax of <NUnit assemblies="[project].nunit" /> to kick off a project file instead of a list of assemblies.  We use NUnit project files to maintain a list of assemblies for testing in the NUnit GUI.  Just store the project file as a solution item is VS2005 and associate it with nunit-gui.exe as the default app to open it, and it's ready at the double-click of the mouse."