I read this blog post while i was running on hacker news. It shows that lots of engineer have wrong understanding about OOP and PP. In addition, while students are learning how to program in OOP way they are just writint classes and because of that they are thinking that writing object oriented code. I strongly advice you to read that blog to see what I say.
If you get that warning it means in your php installation you have no sqlite extension so just install it with that command.
apt-get install php5-sqlite
Zend Framework is a good foundation for everything and can be used also as just a library of various functions. It is also the closest thing to be an "official" PHP framework so there are a lot of developers who know how to use it. It is, however, not a framework you would use to prototype something very quickly.
There are several frameworks that could be used as a quick RAD (Rapid Application Development) tools.
A good example is CakePHP, which is a very popular framework. Fairly easy to learn. It has a lot of sensible defaults and naming conventions that make your life much easier, but which you can override. Continue reading PHP MVC Frameworks