if you create your web application using maven it will get all the required dependencies from you.
If you want to take a look at a web application using jBPM5 you can take a look at the jBPM5 console that it's using it.
You can't include zip files in your classpath, you probably need to include all the jars provided in the binary distribution of jBPM5 to make it work. Not all of them will be required to run a simple processes but at least you will not get the ClassNotFoundExceptions.
Greetings.