After checking out from CVS and building, one should modify the appropriate starter script in the blue/bin directory for your platform to correctly point to BLUE_HOME. After that, running CVS update and rebuilding using Ant should keep you up to date.
While checkins to CVS are almost always done in such a way that the program is in a state which it will compile and function cleanly, it sometimes does happen that a broken checkin occurs. Users building from CVS should be careful to depend on using only a version from CVS if they are not able to fix code to make things compile. If you are not able to fix Java code, then it is recommended to keep two copies of builds from CVS, one which to use for your general use and another for using to test if things will build.