Error BE0029: Unexpected error while executing plug-in '[plugInName]': [error]
This is a generic catch-all error that occurs when the build process attempts to run a plug-in during the build.
Since this is a generic catch-all error, you will need to refer to the text of the error message in order to determine the exact cause of the problem.
If you are unable to resolve the issue and the plug-in is one of the standard ones supplied with the help file builder, post a message in the Sandcastle Help File Builder Discussion group asking for help. For all third-party plug-ins, contact the author of the plug-in for assistance.