From that information, I would guess that the licensing / software protection component utilized by Visual Build (purchased from a now-defunct third party) is preventing the normal ending of the build process. How long has the build been running when this occurs? We've tried to reproduce this behavior with long-running builds launched from a scheduled task but have not succeeded.
One thing you could try is adding a
Kill Process action at the end of the project to terminate the build process when it's done ([
Builder.ProcessID]).