How do I handle error handling in nant build scripts?

I am writing a NAnt build script that is responsible for deploying some files to the iss server. As part of this, I would like to add error handling to my scripts - something I haven't used before.

The introduction of error handling inevitably leads to the thought of the structure of the assembly file (s). I think of structure as a grouping of logic in targets and the dependencies between them.

In NAntContrib I found a task that should make things easier than the standard "onfailure" property. Unfortunately, its the only possible (at least for me) search for short and fairly simple examples of its use. I need guidance on how to create an entire file structure that handles errors for more complex scenarios.