The rest of the error message for that "error=2" error is "No such file or directory". You are trying to run a bat file, you have one (possibly 2) likely errors. At very least, you are treating the Java Runtime.exec() method as if it was a Windows command line. It is not, and so should not be treated as one. Read this article: When Runtime.exec() won't. It will help. Make sure you fully implement all of its suggestions.
Another likely error could be that the path of the bat file isn't where you expect it to be. Make sure you know the 'working' path that Runtime.exec() is using, or use the version of the exec() method that provides an option for you to define the working directory, just to be sure you know exactly where the bat file should be located to be found.