That's impossible to say without seeing the build file. If that really has more than 852 lines (which that error message leads me to believe), then I don't think anyone here can help, because that's WAY too much to read and try to make sense of. Have you tried it with a minimal build file? A basic build file that compiles code and generates javadocs for it shouldn't need more than 50 lines or so, and quite possibly fewer than that.
Ping & DNS - updated with new look and Ping home screen widget
BTW, if you succeed in generating the JavaDocs I doubt they'll be anything more than minimal and useless, given your current JavaDoc comments, but maybe the exercise is simply to learn how to use the JavaDocs generation tool.