No software is bug free (NASA is the closest) and all programmers try to not have bugs so remove that stuff.

I think your question is perhaps more "How do I manage a project without a Project Manager"

My answer to that is:

- Break stuff down into small tasks that you are very confident about estimating time for.  This is key
- Focus on minimal functionality first - login, logout, visit home page, etc. before the real features.
- Use an [Agile][1] methodology.
- Talk to your client daily
- Use software that you, the client and programmer can share for tracking everything (features, bugs and Chores).
- **Make sure** you have a contract. 


  [1]: http://en.wikipedia.org/wiki/Agile_software_development